* remove unneeded casts
* add an informative comment
* add helper function for detecting mpeg2 decoding enablement
* initialise the is_running condvar and mutex in decoder_ctx_t
* removed the consumer thread - moved the code into the writer thread. 
* removed the resizer as we do not need it
* fixed the locking in the writer thread - i now rely on the per-component EOS var
* buggy de-interlacer
* add timestamp
* add init code for the audio queue
* free audio queue upon main thread finish
* Added support for audio stream extraction - packets are directly sent to the audio queue.
* Drop a/v packets without vaild PTS timestamp
* Do not rescale pts timestamp for audio packets.
* demux now copies information about audio stream codec
* remove video.h include - we use encode.h 
* decode_ctx_t now references the audio codec information obtained by demux 
* move definition of the decode_ctx into the encode.h file
* include necessary avcodec.h
* set audio_queue member in the decoder context
* channel layout is also needed
* implemented omx_to_pts to convert OMX_TICKS into a uint64_t number
* copy the encoded buffers timestamp into the final packet
* implemented function to initialise an audio stream 
* implemented function to initialise a video stream 
* added code to initialise output contexts 
* implemented function to write audio frame 
The code is still not ready
* audio queue
* add a switch whether we want to free the data buffer 
* renamed the packet freeing function to reflect its purpose
* added to do
* renamed audio queue to make its purpose more obvious
* added a fixme