Fixing mis-reporting of armed state - missed in b6a8e20.
Fix ANGLE mode and HORIZON mode resetting the errorAngle when they are
both attempted to be enabled at the same time.  Angle mode now takes
precedence over horizon mode.

Fix using aux settings that are not applicable to in-use aux channels -
prior to this it was possible to configure aux4 and then switch to
RX_SERIAL using a 7 channel system (3 aux channels) and aux4 would still
have been processed.
Latest binary with minor fixes.