caps refcounting fixes for float2int fixed wrt setting of caps on int pad with dynamic number of sink pads in float2i...

Original commit message from CVS:
* caps refcounting fixes for float2int
* fixed wrt setting of caps on int pad with dynamic number of sink pads in float2int
* added libsndfile plugin (currently only the src is implemented) - currently only float output, noninterleaved is implemented