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.
Maybe this is evidence that now is a good time to move loadButtonData into JSON files, the way we're currently doing for loadGameData.  My eventual theory was to move all test data to that format, because it's easier to maintain that way and we don't have to worry about Jenkins getting pissed off about repetitive data, i was just being lazy about when to do it.  So maybe now is the time to do it for loadButtonData.