TTS APM Additional Voices

TTS voices for APM Flight Modes (according to APM Master - 12-08-2014)

Two different voices Ava (AV) and Allison (AL) English US

File names are built as:

AVFM0A.wav or ALFM0A.wav or
AVFM0E.wav or ALFM0E.wav

AV or AL - TTS Voice - Ava or Allison

FM99 - Flight Mode Number from APM Sources and corresponding to the
number reported by MavLink

A - After Flight Mode Name the word Active
E- After Flight Mode Name the word Engaged

Why the A or E suffix. Flight Modes can be selected on the radio
(Engaged) but might not remain Active on the Flight Controller. Ex:
Switches on the Radio on Stabilize, Telemetry reports also Stabilize,
if user selects Loiter (Engaged) and there is no GPS available the
Flight Controller remains with Stabilize Active. Lua Script must check
for Flight Mode discrepancy and warn user.