Previous mechanism was exposing possible bug in Qt which would prevent
clicks from work on ToolStrip buttons after cancel MouseArea was hidden.

Also correctly set implicitHeight on QGCTextField

Convert bool settings to SettingsFact

* Holds all the settings for the app
* Allows core plugin to override default values

Use component id from heartbeat

Allow plugin to define default font size, toolbar height and option to display/hide plan view selector.

- Shot Interval in Survey
- Much change to time/distance calc

This makes text show up better on map images

Prevent shutdown ordering crashes