Added more commands.

Replaced Invoke-XbmcUpdateAudioLibrary with
Invoke-XbmcUpdateMusicLibrary.
Added Invoke-XbmcHomeWindow, Invoke-XbmcFileManagerWindow,
Invoke-XbmcPicturesWindow, Invoke-XbmcMusicWindow and
Invoke-XbmcVideoWindow.
Merge branch 'master' of https://github.com/lewishenson/XbmcPowerShell