Added a page to display buttons and sets

Resolves #912

http://jenkins.buttonweavers.com:8080/job/buttonmen-AdmiralJota/342/

This also involved tweaking the python client a bit, so that should be tested too.
This was taken from http://www.cheapass.com/bpu/butnrulz.html. Also, an apostrophe is grammatically acceptable (but not required) for the plurals of things like numbers ("the 90's"), letters ("A's, B's and C's"), abbreviations and possibly some other things I can't recall. Of course, it's possible that the official BM site style guide may be more restrictive.