Added test-script to fetch author of 1st revision

Added API call and JSON-wrangling of result to get the author of the first
revision for a page (to be used to match profile name to wiki username).
API query for getting category pages by timestamp

Added query parameters that will search for pages added to a given category
more recently than a given time.
Added a new category to the lists of skills

Added a new category pair to category_dict that none of the test mentors
have listed on their profile.

Used to test what happens when a learner has listed a category without mentors.
Starting to handle matching errors

First stab at error classes, catching exceptions when there is no mentor match
available.

Currently depends on choosementor, which will change considerably.