Require penzance canvas_sdk in base requirements (for now while version is still considered 'dev').  Add SDK request context settings to environment files.  Set up an instance of the RequestContext at the module level in views.py for the manage sections tool.
Default a missing canvas token to None when building SDK settings for environments.
Merge pull request #69 from Harvard-University-iCommons/feature/integrate_canvas_sdk

Feature/integrate canvas sdk