Fix crash when event listener not created

Build lcd_backlight_hal_emulator.c

When the emulator is set, instead of the lcd_backlight_hal.c file.

Enable and fix compilation of more files

Use ugfx API instead of chibios

Makefile changes to support emulator build

Merge branch 'master' into led

Merge branch 'chibios-contrib'

Update include dir for new serial_link include

Configurable visualizer thread priority

Fix compute_gradient_color

Fix a few led test animation issues

Fix some makefile issues, and symbol issues

Run mirrored keyframes for led tests as well

LEDS are flushed automatically

After running the animation, instead of having to do it manually.
This avoids duplicate flushing, and better support for cross-fades.

Add led crossfading

Add function for running the next keyframe

Add last and first update of frame for anims

Add left to right gradient keyframe for leds

Add fade out for the led test

Add simple led support

Also the first version of a led testing animation