[bootloader][framebuffer] Use unsigned char

The test (c > 127) is always false when char is signed.
Use unsigned char instead.

Change-Id: Iae9dfe800f74702a1fb890b65165e5a402f42977

[zx] Magenta -> Zircon

The Great Renaming is here!

Change-Id: I3229bdeb2a3d0e40fb4db6fec8ca7d971fbffb94

[bootloader][virtcon][font] unify font headers

No reason to hang on to two identical copies of these bitmap fonts.

This will make it easier to switch the kernel to these fonts as well.

Change-Id: Ied1fcb907f4299a8c4c29e5e2fb8c3c723c064e8

[bootloader] Fix framebuffer resolution setting

Apparently clearing the console resets the framebuffer resolution on
some devices, so just don't do that.

Change-Id: I741f009e5f816cc1db6703c8a608f81a07c3b003

[bootloader] Make version text fuchsia colored

- Add a color parameter to fb_font.
- Draw the version string with blt calls instead of using
SIMPLE_TEXT_OUTPUT_PROTOCOL to work around the limited color palette
allowed by EFI SIMPLE_TEXT_OUTPUT_PROTOCOL.

MG-647 #done

Change-Id: I6bf330d0346e54035458929be62650190d7f0f32

[gigaboot] fuchsia logo

Change-Id: I080efaa724db16119c09afd8ac1af7d19e6d1f1b

[bootloader] commandline processing overhaul

- maintain a single central commandline
- simplify interface to this commandline
- ensure that later additions to the commandline
correctly override same-named existing entries
- split legacy boot path into its own file
- bump bootloader version
- display bootloader version next to bootloader name
- disable some debug chatter, declutter things a bit

Change-Id: I86e10bddd156089582bcb079018e5bb780cbbf24

[bootloader] Unique device id.

- Generate a unique device ID based on the MAC Address and the EFF Short
Diceware word list.
- Display using large font device ID prominently.

Change-Id: I81231aa7ca36084e34ba07c724669528bd9075e8

[bootloader] Support the headless mode

When there's no display connected, there is no framebuffer. Magenta
seems to be handling that case, but our bootloader doesn't. This
change adds a couple of extra sanity checks to make sure we don't
die because of null dereference in that case, which seems to be
enough to get the bootloader working in the headless mode. However,
I haven't through the entire codebase and checked every codepath,
so there might still be cases when that might happen.

Change-Id: Id9679a5d10346d335486bc9dbac985bd2ff53da7

[bootloader] Add a boot menu

The only two options so far are selecting a framebuffer resolution and
doing a hard reset.

The framebuffer selection menu lists all the resolutions supported by
the display. After selecting a resolution, the user has 5 seconds to
confirm the choice (in order to prevent a bad framebuffer mode from
making it impossible to use the device). The cmdline param that will
select that mode by default is also displayed on the console.

Refactored much of osboot and framebuffer code to use the global xefi
symbols (gSys, gBS, etc) since we're relying on them implicitly in
printf anyway.
Change-Id: I666641f5868c8c94ee9b8c4ad03961fdd22e958e

[bootloader] Update boot "logo"

Bottom stripe ends up scrolling if the console does, which is weird.
OSBOOT -> GigaBoot
Make more things magenta

Change-Id: I86771268ae53c4834cc74764f681e8e9227bd98d

[bootloader] Move framebuffer functions out of osboot

Change-Id: I94147d6bc80a53d2f9ec45ec307254106812abfa