Updated to ace.dart_0.3.0 and updated ace.implementation to use ACE_PROXY_IMPLEMENTATION per ace.dart's documentation.
Merge branch 'master' of https://github.com/dart-lang/spark into umop-update-ace.dart_0.3.0
Merge pull request #881 from umop/umop-update-ace.dart_0.3.0

Update to ace.dart 0.3.0