0898bca chore: bump version to beta.12 w/ changelog

Author: jelbourn

BUILD_INFO

@@ -1,2 +1,2 @@
-Wed Mar 23 21:26:22 UTC 2016
-d940387bebe62128784974874f59441a0ae5a6bb
+Thu Mar 24 00:24:48 UTC 2016
+0898bca9398f851573743af706b456bd699e86f8

pubspec.yaml

@@ -26,7 +26,7 @@ transformers:
   - $dart2js:
       commandLineOptions:
         - '--show-package-warnings'
-version: 2.0.0-beta.11
+version: 2.0.0-beta.12
 homepage: 'https://github.com/angular/angular'
 authors:
   - 'Alex Eagle <alexeagle@google.com>'