New macro: ACTION_BACKLIGHT_LEVEL(level)

To have full control of the backlight level.
Merge pull request #110 from xauser/master

Enhanced Backlight Support
Updates to CUB's layout
Change PollingIntervalMS to 10ms(Fix #114)
Return when ready check loop is timeouted(Fix #115)
Updates to CUB's layout - rearrange FN-keys
Added example how to handle custom keys
Added support for per-layer FN-translations
Merge remote-tracking branch 'tmk/master' into cub_layout