Jonahstanley/add navigation tests

@jzoldak 
Added in tests for navigating through multiple sections, subsections, sequences:
There is a bit of repeated code in creating the course.  I factored out the repeated parts but since I felt like that the actual creation of the content (the multiple sections, etc.) couldn't be combined in any reasonable way.  Also, I took the already made problem factories in order to create the actual content.  However, I needed to change the method in order to add the problem to a specific section/subsection.

This will also test the ability to come back to the section that the user was working on:
This was done by navigating away and back to the section.

I also had a bit of issues getting the locations of the elements down in the xmodulestore so I used a global variable to store the location