Js testing

This block of work allows us to reliably run pure javascript QUnit based tests from 'make check' (and in the future installed tests).

See ```src/web/test-dummy.html``` for an example test case which does nothing, and see Makefile-web.am for how to add a new test.

I've made QUnit + tap + phantom a lot more reliable in this branch. I've tried to catch most coding errors and make phantom exit (rather than just hang around) in problem cases.

check-journal-renderer is migrated to a 'make check' QUnit and TAP based test.

Although this branch cleans up dbus-test.html a bit, it is still run against test-server (within 'make check'), and that's not going to change for now. It's a good semi-integration test, and does what it's meant to do. Some of the tap-phantom and qunit fixes here contribute to the dbus-test.html stability though.