More hard-coded words in MentionGender

I'm adding some more words that are guaranteed to be male or female in MentionGender, such as 'boy' and 'aunt.' I'm making this a pull request for 3 reasons:
1) Do you see anything that I left off the list?
2) Right now I use a dummy function convertToSingular(), since we're always expecting that lemmaString is singular. Is this the right thing to expect always?
3) Does anyone have any pointers to some lexicon that we can use that will have a more comprehensive list of male and female words (not names, but common words)?