update copyright info

update license to GPLv2 and GPLv3

Remove erroneous comment + fix ipv6_mcast_dbg

Separate debug defines for every module

TFTP: Finish session instead of deleting it when starting timeout timer fails + fix unit test

Issue #387: Added some more checking/freeing stuff/todos

Issue #387: Check return value of pico_timer_add() and pico_timer_add_hashed()

Enforced style via uncrustify

Implemented some specific improvements suggested by the Abstract
Interpretation tool

Revamping timer API to fix #308

TFTP: minor coding style fixes

Fixed 99% of clang compiler warnings.

Added -Wmissing-prototypes, some signature changed.

Initial support for MT7681 platform

Updated Copyright information.

Coding style enforced.

Fixed compiler warning (CC: @dpmik)

pico_tftp_get now return only payload data (issue #221)

Debugging stuff removed

Implements application driven interface for TFTP (Barebox community request #193)

Fixed an issue with the TFTP timers

Implements TFTP Option Extension: RFCs 2347 and 2349 (Barebox community request #192)

TFTP implement an adaptive timeout (as required in RFC1123 and asked in request #188)

Fix few memory handling issues

Reduced code complexity

Improved readability

Duplicated code reduction

Implements TFTP multiple concurrent transfers (Barebox community request #183)

Ran make style

Fixed improper handling of error condition in pico_tftp_start_rx and pico_tftp_start_tx (fixes bug #186)

Refactored picoapp

Fixed coding standards violations in pico_tftp

Removed one last compiler warning from tftp (spotted by TIOBE TICS)

Fixed 2 compiler warnings in tftp

TFTP: Fixed compatibility of put mechanism.

- Added functional tests for put.
- Verified compatibility with tftpd + tftp client (hpa version)

TFTP: Timeout implemented. Quality improved via unit tests.

Added some unit tests for TFTP

Reduced complexity of some tftp function

Working TFTP client + server. Functional tests.

TODO:
- implement timeout
- unit tests
- manual

TFTP client is now working (no timeouts).

TODO: Server, timeouts.

Removed compile errors. Still WIP.

TODO:
- Request, initial handshake
- Implement timeouts

Added initial draft of tftp module. Work in progress.