* bin/common_range.hh: Store the common definition of words.
* bin/autfilt.cc: Use it.
* bin/ltlfilt.cc: Likewise, and implement those two options.
* tests/core/acc_word.test: Test them.
* doc/org/autfilt.org: Augment the last example to point out
that it can now be done with ltlfilt.
* NEWS: Mention the new options.