Add a get_settings method for JS Extensions

Review Request #7968 — Created Feb. 17, 2016 and submitted — Latest diff uploaded

Information

Djblets
release-0.8.x

Reviewers

The JSExtension class now has a get_settings method that returns, by
default, the associated extension's settings. This method can be
overrided by subclasses to provide different settings at initialization
time.