Incorporated REGEX matching

I improved part of the MileageAdder class functionality by using REGEX
matching to count days instead of just looking at the number of
characters in each token as the program did previously. This should
better handle odd cases that might have been erroneously counted as
days.
Further improvement to REGEX, test files

Now the REGEX matching actually checks for instances of months (e.g.
Jan, Feb, Mar...) instead of just groupings of three non-digits. Also
fixed the 2007 test file which was missing two weeks, and updated the
2014 file.