* ALT keymap update
Added additional End key on layer 1 to match key cap
* LED driver update addressing PR #3871
Update sync between IS31FL3733 drivers is causing varying behavior in keyboards including brightness mismatch and slight flicker at very low rgb values. Visually, disabling sync is not noticeable. Ref PR #3871 by guarnacciaa.
Added support to enter bootloader from software (bootloader version must be newer than "v2.18Jun 22 2018 17:28:08" until workaround for older is created).
Updated CTRL and ALT keymaps for entering bootloader with Fn+b held for >500ms.
Added basic MacOS keymap for ALT.
USB sleep LED indicator now turns off after 1 second.
Slowed down debug LED code printing.
Renamed keyboard alt67 to alt and adjusted necessary files where alt67 appeared.
CTRL keymap fixed enum structure name.
usb2422 removed stray define no longer used.
