Feature/view class list for section

Merging in Roderick's slider implementation from LTI_templates branch.   Add a new view function that returns a class list in the context of a given section, where the rendered view of enrollments only shows those enrollees who are not in the given section.  Use SDK methods to retrieve both lists, while filtering out test students.  Update HTML in section details and add javascript that slides right pane in and out and retrieves the section class list on initial click.  Added new test module for the new view function.
good change -- default display 'no users' message depending on presence of data rather than count.