implemented ExitWindowsEx to shutdown, restart the system or logoff the user
separated Suspend & Hibernate
removed obsolete SystemSettings.cs
Merge remote-tracking branch 'origin/FEAT_SystemStateChanges' into WIP_WinterRelease

Conflicts:
	MediaPortal/Source/Core/MediaPortal.Common/Runtime/ISystemStateService.cs
	MediaPortal/Source/Core/MediaPortal.Common/Services/Runtime/SystemStateService.cs
	MediaPortal/Source/Core/MediaPortal.Utilities/SystemAPI/WindowsAPI.cs
Added reference to SlimDX assembly, otherwise plugin could not be enabled on some systems

Signed-off-by: morpheusxx <morpheus_xx@team-mediaportal.com>