New DUAL_AIL MODE A/B configuration (DIP SW and connection change).

old configuration:
VTAIL_SW and DELTA_SW = REV means DUAL_AIL
AIL_SW == NOR means DUAL_AIL MODE A where PB3 11 AILR_IN instead of AUX_IN (no remote gain)
AIL_SW == REV means DUAL_AIL MODE B where PD2 2 AILR_IN instead of ELE_SW

new configuration:
VTAIL_SW and DELTA_SW = REV means DUAL_AIL (same as before)
ELE_SW == NOR means DUAL_AIL MODE A where PB3 11 AILR_IN instead of AUX_IN (no remote gain)
ELE_SW == REV means DUAL_AIL MODE B where PD1 1 AILR_IN instead of AIL_SW
(need to leave AIL_SW in NOR position)
(also, do not connect connect the RX pin to RX VCC)

see http://www.rcgroups.com/forums/showpost.php?p=25339772&postcount=1228 for the connection diagram.

also, removed MOD_PCINT0 (sorry jrb :)), which uses an alternate ISR (but required hardcoded pins). i don't think anyone is using this. will restore if that is not the case.

first build with this new DUAL_AIL MODE B configuration is 20130622_RX3S_V2.