Wordlists with capital letters don't work

I received an email from a user (Malcolm) who had trouble with a word list full of capital letter words. I remember deciding not to worry too much about that when I was writing the code, but this should be fixed either by documenting the fact that lowercase words are required or by fixing it someplace in the code.

There is a more efficient way of doing this that converting the wordlist to lowercase once it has been read. I'll investigate when I have time.