Add implementation for a shallow map watcher
Add in check for map on return type of functions
Add comments
Fix watcher for order dependant maps
Add order dependant map watchers
Merge branch 'master' of https://github.com/dart-lang/web-ui
Add tests with null values to cover first design flaw
Add comments
Added myself to Authors
Merge pull request #443 from tsander/master

Add a _MapWatcher