Remove recursive make for "misc" subdirectory

This was the last remaining vestige of the "all-recur" recursive build.

Also remove the embryonic shared library rules for libbam.so.1 and
libbam.1.dylib, which never fully versioned the shared objects.
Tidy up makefile

Add the conventional $(CPPFLAGS) and $(LDFLAGS).

Remove the htslib-specific parts of the version number calculations,
and put the comments back.

Also add a "tags" target.
Fix typo, remove razip vestige [minor]