More work on mission item indicators

Fix SplitSegment insertion

Handle cross fact update internally

Don't query terrain if no location

Use new SplitIndicator control

Allow split of current segment

Correctly handle command changes from no-coordinate item to coordinate item

Remove unnecessary signaling

Use QmlObjectListModel::begin/endReset to keep Qt from blowing it's brains out with too many updates

Remove testing ifdef

Directions arrows in Fly View

Fix initial load for Plan view

Fix missing waypointLinesChanged signal. Remove unnecessary directionArrowChanged signal.

More work on direction arrows

New MapLineArrow control

Make visibility work

Toggle Rally Point insertion on/off.
Highlight current Rally Point and current Waypoint.
Use tab bar instead of a row of radio buttons for selection (Mission, Fence, Rally).
Fix QGCHoverButton to handle proper checked state toggle.
Get rid of the many arrays used to define behaviors for the ToolStrip. They are now all defined within its model.
Fixed color for disabled text within ToolStrip (it was invisible)

There are no editable parameters and without this, you are presented with a raw list of all 7 parameters to edit.

Update all files that use a QML Menu item to QtQuick.Controls 2.4 to solve the issue of a menu showing up in random places on Android.

Fix incorrect reference to vehicle causing crash

Tree contains all commands

Add support for geofence return point. Also fixed a bunch of bugs in geofence and rally point support.

Fix incorrect isManualCamera logic

Fix initialization

Pattern Preset support

Change-Id: I80acc497ef8fc574f64b181a8d276c5b00d4e057

Heading: Switch from Radians to Degrees