Updated sendCommand() to give full control on MPlayer pausing behavior.
error VideoAlreadyBeingPlayed
methods play (MPlayer + API)

pb:
- need getVideoState()
- pb with reportError
method play (MPlayer +API)
pb with sendCommand("pause") in MPlayer
retrive an include
Merge branch 'feature/play' of https://github.com/heffebaycay/mplayer-plugin into feature/play