* src/misc/satsolver.hh, src/misc/satsolver.cc: Present
the SAT solver as an object with a stream interface, to
prepare for a better implementation.
* src/tgbaalgos/dtbasat.cc, src/tgbaalgos/dtgbasat.cc:
Adjust to the new interface, removing all the handling
of temporary files.
* src/tgbatest/readsat.cc: Adjust.
* src/misc/satsolver.cc, src/misc/satsolver.hh (satsolver_get_solution):
New function, that accepts a solution split on multiple 'v ' lines.
* src/tgbaalgos/dtbasat.cc, src/tgbaalgos/dtgbasat.cc (get_solution):
Remove, and adjust existing code to use satsolver_get_solution().
* src/tgbatest/readsat.cc, src/tgbatest/readsat.test: New files.
* src/tgbatest/Makefile.am: Add them.
* src/bin/man/spot-x.x: Mention the SAT competition rules for
the expected input/output format.
Uses the value of the SPOT_SATSOLVER environment variable
to decide how to call the SAT solver.
* src/misc/satsolver.cc, src/misc/satsolver.hh: New files.
* src/misc/Makefile.am: Add them.
* src/tgbaalgos/dtbasat.cc, src/tgbaalgos/dtgbasat.cc: Use satsolver().
