Upgrade to Modeshape 4.0.Alpha4

Fixes https://www.pivotaltracker.com/story/show/70387904
@awoods: the Modeshape 4.0 guides says you can configure indexing:

https://docs.jboss.org/author/display/MODE40/Getting+Started#GettingStarted-ConfiguringaModeShaperepository

But (even after fixing the invalid JSON so it parses), that gives an error saying that "query" isn't defined and not allowed.  So I guess I'll file a Modeshape bug for that.