This function is called automatically when a QSettings object is destroyed,
so is rarely needed to be called explicitly.

There are still some cases where
a QSettings object is passed-by-reference, so there I left the sync() calls as
it's unclear how permanent those objects are and if they'd call sync() before
application shutdown

Delete of last link would cause crash. Need to check for -1 which
signals no selection in combo box.

- NAN not available in windows headers, use cross platform friendly
version
- VS compiler does not allow initializing non-integral types in header
files
- ActiveQt libs are already installed by Win Qt4.8.5, no need to build.
Plus this part of the makefile just loops without nmake.exe installed
which is not part of a standard windows box

Renamed getNominalDataRate to getConnectionSpeed. Also added upstream/downstream data rate functions to all Link classes.

Simplify calculations by assuming we only care about rates in kB/s.

Hotfix: Fixed widget / UAS initialization order which led to text messages (and other updates) being ignored if the widget was not open when the UAS was created

Erros casused by all of the mergedd branches are now fixed for qgroundcontrol.pro. Working on fixing the errors that now appeare in qgcunittest.pro.

qgcunittest.pro now compiles and runs as long as run in terminal in projcts->Run Settings is unchecked.

Runtime issues resolved, quick application startup and good runtime stats: 0.3% load in idle mode, 15% load showing map and UAS list. Map has a zooming issue, but should be resolvable

Fixed a bug where non-auto hold in the debug console induced 100% CPU load even when the widget was hidden