Vm::_execute() and Vm::_liveCheck can be const now.
Reordered arguments of Vm::_executeNewThreads() to be consistent with
the other _execute*() functions.
Cleanup.
Actually use the return value of _execute(). Stop uselessly setting the
PC of Threads which die on non-epsilon instructions to ProgEnd. Return
true for FINISH_OP to ensure that those Threads are passed on to
_executeEpSequence(). 25% performance improvement on Twain test.
Missed test.
Typo.
Don't read beyond the end of the buffer in Vm::startsWith(). Remember
that the filter is 2 bytes wide.
Renamed autogenerated search tests to distinguish them from the
autogenerated startsWith tests.
Added startsWith tests. Generated by:

  ../src/re_gen/forms 2 | ../src/re_gen/inst abc. '' '' '+' '*' \
    '?' '+?' '*?' '??' '{0,1}' '{2}' '{1,2}' '{2,}' '{0,1}?' '{2}?' \
    '{1,2}?' '{2,}?' | ./pat2swith.py `../src/re_gen/debruijn 3 abc`
Renaming test files: searches -> search
Added multipattern startsWith tests.
Ignore some files generated by 'make check'.
Moved manually written startsWith tests to their own file.
Handle the case where the text is only one byte long. We shouldn't use
the two-byte filter there, as we'll overrun the end of the text.
No point in calling closeOut() and reset() if we never started any
Threads.
Fixed an unused variable warning, in a rather lame way.