Removed INBOX check inside IMAP protocol's GetFolder method

Signed-off-by: Axel Dörfler <axeld@pinc-software.de>

IMAP: Fixed stream vs. parse exception handling.

* Protocol::HandleNextResponse() will now exit when a stream exception
occurs.
* This should fix bug #12601.

IMAP: Use BStringList instead of STL vector.

IMAP,POP3,NewMailNotification: fixed x86_64 build.

* Notifier::HeaderFetched(): fixed the method signature (go figure how it could
build on x86).
* POP3: fSizes type is now std::vector<size_t> instead of BList. Please review.
off_t might be a better choice.
* added the mail_daemon add-ons to the Haiku package again.

imap: WIP of getting fetching headers to work.

* Changed the FetchListener mechanism quite a bit.
* Doesn't seem to work correctly yet, although most pieces are in
place now.

imap: Fleshed out command processing.

* Still doesn't do anything useful, though.

imap: Work in progress of connection setup.

* SelectCommand now correctly encodes the mailbox name again.
* Hierarchy separators from the LIST/LSUB commands are now properly parsed,
and taken into account.
* Folders in the file system are now created for mailboxes on the server,
supporting hierarchical mailbox names.
* A connection worker now has an IMAPFolder that handles the local side of the
mailbox, and an IMAPMailbox that handles the server side.
* Connection workers are now created/deleted, and setup correctly. They will
now also wait in case they don't have a mailbox until they get some.

IMAP: The connection workers are now started.

* On SyncMessages(), the main connection worker is started if it is not already
running (it may only run already in idle mode).
* This will then list the subscribed folders, and create as many more connection
workers as allowed and make sense.
* Finally, it will distribute the folders to the workers which don't do anything
further yet.

Completed literal handling.

* LiteralHandler commands now receive the literal data as intended.
* The 'fetch' command in the imap_tester now uses this to print the literal
to stdout.

Started working on the IMAP add-on itself.

* Renamed imap_config.cpp to ConfigView.cpp, IMAPFolderConfig.(h|cpp)
to FolderConfigWindow.(h|cpp).
* Got the latter to build.
* Added Settings class to simplify and unify the BMessage based
settings access.
* Removed the InboundProtocol[Thread] implementation from the build for now.

Read some more specs, cleaned Protocol a bit.

* Added some TODO comments based on the various IMAP specs and extensions.
* Removed SelectMailbox() functionality from the Protocol class; it's not
really useful to have it there.
* Removed some other methods that don't belong into the Protocol class.

More work in progress of the IMAP rework.

* Implemented FetchCommand, and some more.
* Improved and extended the imap_tester.
* The base to implement the new InboundProtocol on is now mostly done, at least
for a start.

Got rid of the ConnectionReader, and implemented parsing literals.

* The parser now works on a BDataIO instead. It's now even a bit simpler
overall.
* Implemented ParseLiteral() - the default implementation just reads the data
into a string. Thanks to BDataIO this was now very simple to do.
* Tested the code: imap_tester can now successfully read mails (using the raw
command only, at the moment).

Work in progress of rewrite; IMAP doesn't even compile at this point.

IMAP,POP3,NewMailNotification: fixed x86_64 build.

* Notifier::HeaderFetched(): fixed the method signature (go figure how it could
build on x86).
* POP3: fSizes type is now std::vector<size_t> instead of BList. Please review.
off_t might be a better choice.
* added the mail_daemon add-ons to the Haiku package again.

imap: WIP of getting fetching headers to work.

* Changed the FetchListener mechanism quite a bit.
* Doesn't seem to work correctly yet, although most pieces are in
place now.

imap: Fleshed out command processing.

* Still doesn't do anything useful, though.

imap: Work in progress of connection setup.

* SelectCommand now correctly encodes the mailbox name again.
* Hierarchy separators from the LIST/LSUB commands are now properly parsed,
and taken into account.
* Folders in the file system are now created for mailboxes on the server,
supporting hierarchical mailbox names.
* A connection worker now has an IMAPFolder that handles the local side of the
mailbox, and an IMAPMailbox that handles the server side.
* Connection workers are now created/deleted, and setup correctly. They will
now also wait in case they don't have a mailbox until they get some.

IMAP: The connection workers are now started.

* On SyncMessages(), the main connection worker is started if it is not already
running (it may only run already in idle mode).
* This will then list the subscribed folders, and create as many more connection
workers as allowed and make sense.
* Finally, it will distribute the folders to the workers which don't do anything
further yet.

Completed literal handling.

* LiteralHandler commands now receive the literal data as intended.
* The 'fetch' command in the imap_tester now uses this to print the literal
to stdout.

Started working on the IMAP add-on itself.

* Renamed imap_config.cpp to ConfigView.cpp, IMAPFolderConfig.(h|cpp)
to FolderConfigWindow.(h|cpp).
* Got the latter to build.
* Added Settings class to simplify and unify the BMessage based
settings access.
* Removed the InboundProtocol[Thread] implementation from the build for now.

Read some more specs, cleaned Protocol a bit.

* Added some TODO comments based on the various IMAP specs and extensions.
* Removed SelectMailbox() functionality from the Protocol class; it's not
really useful to have it there.
* Removed some other methods that don't belong into the Protocol class.

More work in progress of the IMAP rework.

* Implemented FetchCommand, and some more.
* Improved and extended the imap_tester.
* The base to implement the new InboundProtocol on is now mostly done, at least
for a start.

Got rid of the ConnectionReader, and implemented parsing literals.

* The parser now works on a BDataIO instead. It's now even a bit simpler
overall.
* Implemented ParseLiteral() - the default implementation just reads the data
into a string. Thanks to BDataIO this was now very simple to do.
* Tested the code: imap_tester can now successfully read mails (using the raw
command only, at the moment).

Work in progress of rewrite; IMAP doesn't even compile at this point.