* src/hoaparse/parsedecl.hh (hoa_abort): New structure.
* src/hoaparse/hoascan.ll: Throw hoa_abort on --ABORT--.
* src/hoaparse/hoaparse.yy: Deal with this exception.
* src/hoaparse/public.hh: Add a boolean flag to mark aborted automata.
* src/bin/autfilt.cc: Report aborted automata.
* src/tgbatest/hoaparse.test: Add test case.
* src/hoaparse/hoaparse.yy: Allocate state after parsing the entire
header, not right after passing "States:".
* src/tgbatest/hoaparse.test: Reflect improved error message
about initial state.
* src/hoaparse/hoaparse.yy: Improve error recovery,
and fix location tracking in streams.
* src/hoaparse/public.hh: Store the last location so
that the next parse start at the correct position.
* src/bin/autfilt.cc: Stop parsing a stream on irrecoverable errors.
* src/tgbatest/hoaparse.test: Adjust tests.
