Add sharelatex testing

Created by: iainbryson

It would be very useful to have a an end-to-end test for the sharelatex. i.e

create a rake task which:

(1) Creates a test account in 00000 sharelatex (2) Create a project in 0000 sharelatex using a test zip (3) update the config sharelatex enote project id for the course, restart the course to pick up the new config (4) test the sharelatex update from the course (i.e. getpdf compiling the test enotes, copying them to the course and populating the enote menu)