Remove orphaned prototype for sr_filter_channels from proto.h.
SWIG: Remove obsolete lowlevel wrapper methods for sr_output_format.
SWIG: Rename libsigrok.i to lowlevel.i.
Python: Add support for session source callbacks in lowlevel wrapper.
Give type names to all enumerations.
configure.ac: Separate library flags from other CFLAGS.
Add C++ bindings.
Python: Reimplement high level bindings on top of C++ ones.