* iface/gspn/eesrg.cc, iface/gspn/eesrg.hh,
iface/gspn/dottyeesrg.cc: Rename as ...
* iface/gspn/ssp.cc, iface/gspn/ssp.hh, iface/gspn/dottyssp.cc:
... these.  Adjust all classes and function names.
* iface/gspn/ltlgspn.cc, iface/gspn/Makefile.am: Adjust all classes
filenames and function names.
* m4/gspnlib.m4: Define WITH_GSPN_SSP and LIBGSPNSSP_LDFLAGS.