= cppm update
- cppm as a run time feature. can be selected with stick config.
- can be disabled during compile time (#define DISABLE_CPPM) to reduce firmware size
- support multiple channel orders. currently only one used (RETA1a2x)
- rearranged all the isr handlers. rx3s_v* uses TIMER1_CAPT_vect

= support mixer EPA modes
- mixer endpoints can be set in 3 ways: fixed [1000-2000], fixed [1100-1900] and tracking starting from [1250-1750]. can be selected with stick config.

= attitude
- once enabled, device will try to hold attitude when sticks are centered (+/-100 from neutral)
- rx3s v1 uses AIL_SW to enable attitude hold mode.
- rx3s v2 uses RUD_SW to enable attitude hold mode.
- nanowii or cppm (including rx3s_v*) uses aux2 > 1700 to enable attitude hold mode.

= stick config parameters so far:
// 1=wing_mode 2=roll_gain 3=pitch_gain 4=yaw_gain 5=mixer_epa_mode 6=cppm_mode 7=exit
// wing_mode: see enum WING_MODE
// [roll|pitch|yaw]_gain: see vr_notch_table[]
// mixer_epa_mode: see enum MIXER_EPA_MODE
// cppm_mode: see enum CPPM_MODE
- device will restart after exiting stick config

= enable eeprom write/read of stick config parameters
- now for all devices, not just nanowii
- rx3s_v* will ignore stick config settings on WING_MODE and <axis>_gains (use dip switches and pots)
- eeprom can be reset with boot_check (see next)

= boot check pin pairs
- on bootup, check if specific pin pairs are shorted.
- use case for erasing eeprom: rx3s_v* (AIL_OUT/ELE_OUT) and nanowii (D6/D5).

= whole bunch of optimization to reduce space.
- also, compiling on the ide results in taking more firmware space than from the commandline