support custom meta and custom template data for ac.composite.done() to try to match the api from ac.done(). This solves issue #948
preserving meta info except the meta.view from children.
merging metas accordingly using mojito.util
adjusting examples and tests to use the new API for composite instead of the legacy one
Merge pull request #950 from caridy/compisite-view

issue #948: support custom meta and custom template data for ac.composite.done(). This PR matches the api of ac.done() and ac.composite.done()