Additional parsers for classification data

Since we will be updating these later for current class info, please use
these following the instructions noted in parser_wrapper --help to
create USPC, mainclass and subclass tables using master classification
files from http://www.google.com/googlebooks/uspto-patents-class.html or
similar link at USPTO or ReedTech (the latter actually hasn't updated
yet).
Updated parser and MySQL upload with classes

Phew.. took me some time to figure out with master classification files.
Please use parser_wrapper.py help to see the syntax to first process
classification files and then upload to database. There is obviously
some flaw in actual data (not our fault - same issue on Google Patents)
that reports some inexistent classes on a few patents (my guess like
1%). We can discuss as issue.