CommInterface: use NSAssert instead of assert

- NSAssert won't crash when compiled in release mode
Send a CLEAR_ALL when mission is empty
Assert when requested waypoint is out of range

 - additionally, silenced a number of unhelpfully verbose logging
messages
Correctly handle reading of an empty mission
TxMissionItem/ClearAll share final ack handling logic
Disabled segmented control
Merge pull request #91 from fightingwalrus/igcs-157-appcrash-on-auto-tap

CRASHING BUG - CommInterface: use NSAssert instead of assert
Merge pull request #93 from fightingwalrus/igcs-166-disable-auto-segmented-control

Disabled segmented control
Settings and Follow Me moved to bottom of sidebar

- follow me button disabled
CocoaLumberjack added to project

 - as at v1.9.2 (09b65ed)
Enable TTY logging
Switching (legacy?) BT code to lumberjack

 - for completeness
Switching legacy GK code to Lumberjack

 - for completeness
Switch misc views/controllers to Lumberjack

 - removed unnecessary logging in places
Mission editing switched to Lumberjack
Comm logging switched to Lumberjack
Radio config switched to Lumberjack
FWR code switched to Lumberjack
Removed unused function
Switched to Lumberjack