* 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.