add an initializer for adding tags, with a test
more tests for BrooklynNode, including test which uses REST API of local instance (and new "SameBrooklynNodeImpl" semi-mock); and adds BrooklynEntityMirror with test
support effector parameters which are maps (@sjcorbett just did this also; now this commit simply adds a test for this)
fix intermittent failing test by ensuring we wait for persistence to complete