- new servo out (flexible pin assignments)
- dual ailerons mixing
- read switches first to determine pin config
- general cleanup
- yet another servo out implementation
- clean up switch mode check
v2 definitions
debugging and cleanup. a couple of open issues:

- would like to save txd/rxd on the v2, so what pin to use for ailR-in? (probably one of the ele/rud sw)
- delta_sw needs to be read via adc first (delta_sw_vr) then translated to delta_sw_vr.
- i think i broke servo out (after rewriting it twice). need to debug it..
just found out pin 14-19 in arduino maps to a0-a5, so there should be no need to use the adc to read delta_sw.

updated v1 assignments to match original as default and then remap them again on ail_mode changes.
bug fixes:
- fixed servo output code (init and isr)
- added all-servo sweep to dump_sensors()
- cleaned up ailr_out for AIL_SINGLE mode. delay till output stage.

will need to revisit
- servo out code again. instead of fixed pulse width, perhaps use the end time to compute next wait interval. but check in this fixed version first.
- rx in code, perhaps have common code (macro) for rx in (now in 3 places) and set ailr_in = ail_in in AIL_SINGLE mode there. then the rest of the code assumes AIL_DUAL mode.
move ail_mode handling to input side (for calibration and main loop), so set ailr_in = ail_in on AIL_SINGLE mode. rest of code assumes valid ailr_in. but still not common input code yet.

fixed bug in AIL_DUAL mode A.
more bug fixes:
- mixer should use *_in2, which is a safe copy of _*in.
- dip sw definitions are reversed (0 mean rev/on, 1 means norm/off).

tested on rx3s single aileron mode and [norm, delta, vtail] mixing. next to test on dual aileron mode.
corrected default pin assignments for v2.
disable serial
Merge remote-tracking branch 'remotes/origin/dev'