feat(metadata extractor): Cache the fieldMetadataExtractor for greater performance

Dartium tests run in 7.6s; down from 18.2s.
dart2js on Chrome runs in 2m instead of 3m
chore(bootstrap): rename: ngDynamicApp -> dynamicApp; NgApp -> Application
fix(export): Add missing NgController to angualr.dart
test(ng_model): detect browsers that do not support `simulateTypingText`

Detect browsers that do not support `simulateTypingText` and skip tests
that rely on it.

Closes #814
chore(karma): Use Dartium launcher.

There is a Dartium launcher (in karma-chrome-lauchdr) which can be used to launch Dartium browser in checked mode. There' no need for using ChromeCanary to launch Dartium any more.