Remove validation of `attrs` in _get_request_object

Validation is performed downstream, so this call is redundant. In
addition, `attrs` can also now be a list which supports the new DataView
facets format.
Change test DataView json structures to use the new facet format

This suppresses the deprecation warnings emitted by Avocado.
Add support for setting the `context_json` on set instances

If the model has a `context_json` field, this will allow persisting
the original context that was used to create the set. Note, this only
applies to new instances, so the original context is not overwritten.

Fix #159
Fix requirements.txt to use the master branch of Avocado

Update 1.4.x and 1.5.x Django point versions
Update README badges to use master branch
Merge pull request #160 from cbmi/issue-159

Add support for setting the `context_json` on set instances
Update SessionMiddleware to bypass CSRF if request token is present

For non-session-based authentication, Serrano resources handle
authenticating using a token based approach. If it is present, CSRF
must be turned off to exempt the resources from the check.
Add more exporter resource tests

Found these in a stash, might as well put them to use
Remove TEST_NAME for use of in-memory SQLite database during testing

See https://docs.djangoproject.com/en/1.5/ref/settings/#test-name
Port resources to cache instance in `get_object`

This is a more obvious approach than caching it in the `is_not_found`
handler.
Implement a stats endpoint for context and query resources

Fix #143
Add link to stats endpoint in context and query posthook
Merge pull request #162 from cbmi/issue-143

Implement stats endpoint for context and query instances
Add DOC and integrate script for Travis

Signed-off-by: Byron Ruth <b@devel.io>
Merge pull request #164 from cbmi/doc

Add DOC and integrate script for Travis
2.3.3 Release

Signed-off-by: Byron Ruth <b@devel.io>
2.3.4 Beta

Signed-off-by: Byron Ruth <b@devel.io>
Replace HttpResponse with Resource.render calls

This ensures responses are processed by the resource and consistently built.
Messages have been added to all responses in the 4xx-5xx range.

Fix #166, #167

Signed-off-by: Byron Ruth <b@devel.io>
Merge pull request #169 from cbmi/issue-168

Replace HttpResponse with Resource.render calls
Use __unicode__ representation in Field and Concept templates

This pushes down the logic of choosing a name down to Avocado.

Signed-off-by: Byron Ruth <b@devel.io>