Drift Mode support

Add a color for Drift mode in KML creator.
Add an entry in the Flight mode list for Drift mode.
Typo for Fly-By-Wire A reported as B for APM:Plane
Fix outdoor style to grey widgets when disabled
Enable http link in about box to launch system web browser
Fix issue with Cam Gimbal View Tilt Input channel changing incorrectly, on Roll change
Fix issue when editing waypoints in 'Offline Edit Mode' that it would crash.
Python SiK Uploader script
Changes for display of "live" vs "log" label on AP2DataPlot, as well as some bugfixes to prevent crashes when switching between log and live plot viewing
Fix for compile error due to a bad header
Throw a warning for AC 3.1+, that the props will spin when rearmed
Changes to support the new MAVLink low latency options
Fix to display APM Planner 2 instead on QGC in warning message
Fix to allow Mission Planner created missions files to be loaded in Flight Plan Widget
Fix to add Drift mode as a definition in ArduPilotMegaMAV object
Fix missing DRIFT conversion in UAS Action Widget
Fix corrupt packet detection in 2D Plot View
Beta-RC2
Created new ApmUiHelper class to populate comboBoxes with modes
This give greater consistency across the application.
Fixes issue with modes incorrectly displayed with APM:Rover
Add Plot View Button to toolbar
Hide connection button for UAS when 3DR Radio Config view selected