Add ExtensionMiddlewareRunner middleware

Review Request #4563 — Created Sept. 12, 2013 and submitted — Latest diff uploaded

Information

Review Board
release-1.7.x

Reviewers

Add ExtensionMiddlewareRunner middleware from djblets.

All tests pass:

Ran 746 tests in 68.571s

OK (SKIP=12)

The skipped tests are all related to perforce, which I don't have installed. They should be unrelated to my patch.