Fixes trailing white space

Hi,

I think it's quite common to have Vim, your editor or your IDE automatically remove trailing white space upon saving a **.py** file. Every time I edit a file and look back to see what I've changed the diff contains many lines that I haven't even touched.

This pull request removes all trailing white space. So anybody else who has trailing spaces automatically removed won't have the same issue.

Cheers,
Matt