more elaborate checks, they also work now

first version of CPM code

Adding typedef for uint64_t and int64_t so we can use them through SWIG.

Removing warnings in portaudio source/sink.

Fixing output types from tap_type to o_type in gr_single_pole_iir.h. Doesn't make a difference in the current uses of this class, but could in the future. Thanks to Achilleas Anastasopoulos for pointing this out.