[reactive] 'stateE' --> 'mealy'

I renamed 'stateE' and 'stateE_' to' mealy' and 'mealy_' in reactive-0.9.4 (just released). I've been meaning to change these names for a while now. I prefer these new names as being more clear & specific and connecting clearly to automata theory rather than to imperative programming. Please update your code if you use either function. David -- would you tweak the Events tutoriahttp://netsuperbrain.com/blog/posts/introducing-reactive-events/l accordingly? - Conal