Fix #283, accel calibration getting stuck/out of sync

Added in functionality for a countdown timer to let users know how long
they have left to continue the calibration procedure. Once it times out,
APM will automatically move on to the next step, and "continue" will need
to be clicked continuously to cancel out. Ardupilot pull req #1003
addresses this. This fix also adds in new LinkInteface functionality,
enableTimeouts() and disableTimeouts() to enable/disable auto-resetting of
APM on communications silence.
Removed a commenting out that accidently got commited
Configuration: Allow custom data rates
Linux: Changed busy-serial-port error message to reference modemmanager
Linux Packaging: better compatibility with .deb standard
Advanced Param List: Fixes #153 Add ranges/defaults for params to view
Merge branch 'master' into mac64
MAVLink: Fixes #310 tlogs to be compatible with MP/MAVProxy
Terminal View: Fixes Terminal to not show the MAVLink connect button

Fix up Terminal View so it disables the connect button in terminal if connected to an active MAV to make it more clear that you need to connect below.
Also fixed the issue of not remember the last save port.
MAVLink: removed accidentally added member variable
Addition of tlog replaying capabilities
Added play/pause to datalog reply, and sped up some things
Renamed a typo in TLogReplayLink, and changed so it now hides the connect button when replaying a log
Removed XBee dependancy since it is currently unused
Addition of throwAwayGCSPackets which causes the MAVLink protocol parser to ignore any packets with the 255 GCS system ID
Changed UASManager function to properly delete UASInterface* objects when requested, and fixed issue where the UASListWidget wasn't actually removing a UAS when it is deleted
Fix for crash after removing a UAS, then re-adding it, caused the FlightModeConfig screen to get in a bad signal state
Changed TLog loading so the toolbar stays hidden if the user doesn't select a file to load
Change to allow enable/disable of connect widget to be overridden
Fix for TerminalConsole show/hide of connect widget

The TerminalConsole was not checking to see if it was the currently
visible window before attempting to show the connect widget, this is fixed