Feature/sections sm1

1) Backend changes for sorting the list of users in the section(TLT 311 backend) . Sorting by 'sortable_name' field provided by Canvas. UI integration to be done after Roderick's design
2) Changes to pass in section name to section details screen so that section name is displayed(TLT 297)
3) UI integration for section details screen
4) A few test cases to check for section name attribute 
The section_details url seems like a good candidate for a RESTful url, like /sections/{section_id}.  The id is always expected to be part of the url, so it makes sense to have it as part of the path with regex - this would not only be in line with other tool urls in our ecosystem, but it would prevent the need in the view controller to test if a section id was passed in and if the id was numeric since it would only resolve to that view with those conditions being met.  An example of such a url pattern is:
url(r'^sections/(?P<pk>\d+)/$'
With the above, you'd get the section_id in the request kwargs as 'pk'.