* spot/twaalgos/dot.cc: Honor the "state-player" property and draw
player 1 states using diamonds.
* doc/org/hoa.org: Show an example.
* tests/core/gamehoa.test: Make sure diamond is output.
* NEWS: Mention this.
* spot/parseaut/parseaut.yy, spot/parseaut/scanaut.ll,
spot/twaalgos/hoa.cc: Add input and output support.
* doc/org/hoa.org: Document the HOA extension.
* bin/ltlsynt.cc: Add a --print-game-hoa option to
produce such format.
* tests/core/gamehoa.test: New file to test this.
* tests/Makefile.am: Add it.
* NEWS: Mention this new feature.