(tgba::project_state): New method.
* src/tgba/tgbaproduct.hh, src/tgba/tgbaproduct.cc
(tgba_product::project_state): New method.
* src/tgba/tgbabta.hh, src/tgba/tgbabta.cc
(tgba_bta_proxy::project_state): New method.
* src/tgbaalgos/magic.cc (magic_search::print_result): Take
a restrict argument.