Adds a convert from Sequitur G2P xml fst to serialized s4 fst

Thanks to Johannes Twiefel and Timo Baumann

Fixes issue #394



git-svn-id: svn+ssh://svn.code.sf.net/p/cmusphinx/code/trunk/sphinx4@12522 94700074-3cef-4d97-a70e-9c8c206c02f5