Merge in the latest dsd and mbelib from git.

I have no idea whether anything still builds, but I will test that now
and make changes as necessary.
Delete out-of-date paragraph from README.
Modify cmake files for mbelib and dsd to make them build as static libraries.
Fix segfault.
Enable DSTAR in auto-detect mode (to match code change in dsd_main.c).
Update block description to reflect that D-STAR now has audio.
Remove libmbe dependency from dsd's cmake.
Fix dependency issue in DSD's cmake file.