Allow BasicAPIEncoder specialization

Review Request #7849 — Created Jan. 7, 2016 and discarded — Latest diff uploaded

Information

Djblets
release-0.9.x

Reviewers

Subclasses of the BasicAPIEncoder now can specify the JSON encoder
that is to be used. This defaults to the DjbletsJSONEncoder.

Used this with https://reviews.reviewboard.org/r/7822/.