* iface/gspn/Makefile.am (gspn_HEADERS): Add common.hh.
(libspotgspn_la_SOURCES): Add common.cc.
(libspotgspneesrg_la_LIBADD, libspotgspneesrg_la_CPPFLAGS)
(libspotgspneesrg_la_SOURCES, ltlgspn_eesrg_SOURCES)
(dotty_eesrg_LDADD, dotty_eesrg_CPPFLAGS): New variables.
(lib_LTLIBRARIES): Add libspotgspneesrg.la.
(check_PROGRAMS): Add dottygspn-eesrg.
* iface/gspn/gspn.hh, iface/gspn/gspn.cc
(gspn_exeption, operator<<(gspn_exeption), gspn_environment): Move ...
* iface/gspn/common.hh, iface/gspn/common.cc: ... in these new files.
* iface/gspn/eesrg.hh, iface/gspn/eesrg.cc, iface/gspn/dottyeesrg.cc:
New files.