Remove orphaned prototype for sr_filter_channels from proto.h.
Give type names to all enumerations.
configure.ac: Separate library flags from other CFLAGS.
Don't include LOG_PREFIX in the Doxygen output.

(files in hardware/, input/, and output/ don't need this since none of
those directories contain API stuff and are thus not included in the
list of input files for Doxygen at all).
Don't include NO_LOG_WRAPPERS in the Doxygen output.
session: Show unitsize of the received data.
Move public headers into include/libsigrok.

This is needed so that the C++ bindings, the header for which
references "libsigrok/libsigrok.h", can have a valid include
directory passed to build them before the headers are installed.
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.
Add C++ bindings.
Python: Reimplement high level bindings on top of C++ ones.
Add Java bindings.