Split APIv2 into separate files
Make APIv2 use dynamic response representations

The Content-Type of an APIv2 HTTP response will now be dynamically
determined by which types are Accepted by the request.

The actual APIv2 functions now generally return raw Python dicts, making
them more appropriate for being called internally.
Move session creation API endpoint to a more RESTful location
Fix a bug where session's attachments and access control were not deleted
Expose DELETE APIv2 call for individual views
Add GET method for view details to APIv2
Merge branch 'apiv2_refactor'

* apiv2_refactor:
  Add GET method for view details to APIv2
  Expose DELETE APIv2 call for individual views
  Fix a bug where session's attachments and access control were not deleted
  Move session creation API endpoint to a more RESTful location
  Make APIv2 use dynamic response representations
  Split APIv2 into separate files