pass
engine will now pass in turn by returning an empty string instead of a
word
play against file open bug fix.
the referee wasn't getting the word set when opening a file.
genletters improvement.  
I think this is a lot more like what letterpress is actually doing.  
When he mentioned 3-8 vowels, I didn't think about it... but my former
algorithm always used 7 or 8 based on the frequency.  But I see board
swith 3-4 letters all the time.  So now there is a higher chance to have
fewer vowels on the board.
removing a file that shouldn't be here in the first place.