Added bli_info_*() query functions.

Details:
- Added a new API family, bli_info_*(), which can be used to query
  information about how BLIS was configured. Most of these values are
  returned as gint_t, with the exception of the version string which
  is char*.
- Changed how the testsuite driver queries information about how BLIS
  was configured (from using macro constants directly to using the
  new bli_info API).
- Removed bli_version.c and its header file.
- Added STRINGIFY_INT() macro to bli_macro_defs.h
- Renamed info_t type in bli_type_defs.h to objbits_t (not because of
  an actual naming conflict, but because the name 'info_t' would now be
  somewhat misleading in the presence of the new bli_info API, as the
  two are unrelated).