Telemetry: add GCSLowDataRateModeEnabled flag

- If GCSLowDataRateModeEnabled is set to YES
  (NO by default) then we only request a
  limited set of telemetry and don't
  request a mission on telemetry connection
FWR connection: vibrate or beep on connect

- Add SoundUtils class and vibrateOrBeepBeep
  Method which causes iPhone to vibrate or
  beep-beep.caf to be played on other devices
  that don't support vibration

- call vibrateOrBeepBeep on accessory connected
Remove unused constants
Modified default altitude

 - compromise for a/c and quads
Default autocontinue to true

 - apparently ignored by APM
 - required for ar.drone
Merge pull request #100 from fightingwalrus/igcs-187-vibrate-on-fwr-connect

FWR connection: vibrate or beep on accessory connect
Fix label height to constant

 - not the ideal solution, but workable until we drop iOS6
Merge pull request #101 from fightingwalrus/misc-defaults-offthread

Misc defaults offthread
Telemetry: no more double negative

- Rename GCSLowDataRateModeEnabled to
  GCSStandardDataRateModeEnabled
Telemetry: clear up comments re GCSStandardDataRateModeEnabled
Merge pull request #99 from fightingwalrus/igcs-170-add-low-datarate-mode

Telemetry: add GCSLowDataRateModeEnabled flag
Merge pull request #102 from fightingwalrus/igcs-176-ios8-rowheight

Fix label height to constant
Radio Config: always try to start telemetry on cancel

- Calling the startTelemetryMode when cancling radio
  config restarts the device by tearing down EAAccessory
  connection and keeps the device in a better state so that
  subsequent attempts at radio configureation have a better
  chance of working properly.