Regular expressions. For Sequence and Alternative there is a choice between a body of two sub-expression or a list of sub-expressions. I choose the list because it tends to simplify the code, for example be having One and Zero RegExprs as special cases.

TODO
o atoms/ranges of arbitrary bit length
  o default length 16; adjustable
  o atom ::= code [ ":" bits ]
  o an atom is translated into n single-bit transitions
  o FA.mergeTransitions(m)
    o compose m transitions into single transitions
    o caution with end states
  o replace range tests in TableFA by array indexing;
    e.g. scan char by 4x4 transitions
  o caution: reading from an input stream raised byte order issues