DVBAPI plugin for VDR

The plugin allows connect VDR to OScam. It creates a software CAM in VDR,
and communicates with OSCam over camd.socket (using 'dvbapi' module).
This way it pass decryption requests to OSCam and obtains back keys which
are needed for CSA stream decryption. Decryption of the stream is done using
DeCSA libraries (FFdecsa or libdvbcsa).