Add defines for v1/v2/v3 board compatibility

Work in progress new SMPS

Begin TI SMPS design

Remove SMPS in preparation for next attempt

Fix elrs call

Add three new OSD features: - one-letter indicator for armed/disarmed state - one-letter indicator for acro/angle mode - display "BATTERY!" in the middle of the screen once the voltage drops too much

more updates for v1 hardware

Update LEDs for v2 board, rework USB interface

Move schematic PDF to correct location

Add MIT license