MP1-2151 : FEAT-Volume_Overlay
MP1-4574: Allow Windows 10 Preview to be fully supported and added Server 2012 R2 as reference Server OS for Windows 8.1 and 10.
Merge remote-tracking branch 'remotes/upstream/MP1-4574-REWORK-Allow_Windows_10_Preview_install_and_add_Server_2012_R2_to_OS_list' into 1.7.0Fork-BDJ

Conflicts:
	Common-MP-TVE3/OsInfo/OSInfo.cs
Merge remote-tracking branch 'remotes/upstream/MP1-2151-FEAT-Volume_Overlay' into 1.7.0Fork-BDJ

Conflicts:
	TvEngine3/TVLibrary/TvPlugin/TvPlugin/TvFullScreen.cs
	mediaportal/Core/guilib/GUIWindow.cs
	mediaportal/WindowPlugins/Common.GUIPlugins/GUIVolumeOverlay.cs
	mediaportal/WindowPlugins/Common.GUIPlugins/Video/GUIVideoFullscreen.cs