Birth death dates

I added birth and death date support for the gem. #age defaults to birth to current in years if no arguments are passed. I tried to keep arguments passing in as similar to the rest of the query_methods to keep it consistent. I was going to add a :days option, but realized that calculating days per months would take a little longer, so I 
held off on that. I also added more tests to cover the new code. 

If anything needs work, please let me know, my brain is scattered at the moment so mistakes might have cropped up. Or if simply there is a better way to do something I attempted.


I did not realize until now that trailing spaces were stripped off, my code editor has that plugin and I forgot that it was on. If this is a problem let me know.