add generic audio, video and demux headers in zapit/include (TODO: put them into a better place, or put wrappers into lib directories) that automatically dispatch to the hardware specific functions and use them in the code git-svn-id: http://www.coolstreamtech.de/coolstream_public_svn/THIRDPARTY/applications/neutrino-experimental@962 e54a6e83-5905-42d5-8d5c-058d10e6a962