New formula: opengrm-thrax

The OpenGrm Thrax tools compile grammars expressed as regular
expressions and context-dependent rewrite rules into weighted
finite-state transducers using OpenFST.

The formula includes a patch which has been reported upstream. It simply
comments out the initialization of a never-used variable which causes
compiler problems.

The test shows conversion of cardinal numbers (like "170") to word
strings (like "one hundred seventy").