First draft of QGCSettings used to reload comm link settings.
Partly operational for UDP ports only.
UDP link saves and recalls for connection. No auto connect yet.
New link only made in MainWindow and not application
Application using QSystemSemaphore to check if an instance of QGC is already running
Changed link group names for settings storage back to matching the link name
Removed QGCSetting class and QGCSettings.h headers left over from prototype build.
Merge branch 'settings' of https://github.com/crashmatt/qgroundcontrol into settings

Conflicts:
	src/QGCSettingsGroup.cc
Rework of QGCSettings.  Not working.
Fix failure to getGroupName through function
serial and udp link load/save working.
protocols not done.
Delete link not working.
tidied getGroupName into LinkInterface only
CommConfigurationWindow now requests LinkManager to delete not just disconnect
Fixed error messages caused by base class constructors declared in bad order
Working link create, delete, load and save for UDP and Serial
Remove extra settings key extraction from LinkManager
Merge remote-tracking branch 'origin/settings'

Conflicts:
	qgroundcontrol.pro
	src/QGCApplication.cc
	src/QGCApplication.h
	src/comm/LinkManager.cc
	src/comm/LinkManager.h
	src/comm/MAVLinkSimulationLink.cc
	src/comm/SerialLink.cc
	src/ui/MainWindow.cc