fix(ng-attr): remove camel-cased dom attributes

See: https://github.com/angular/angular.dart/pull/560#discussion_r9718101

Closes #567
refactor(pub): Simplify support for pub transformers

Slight refactoring of expression extractor to make it easier to drive from Dart transformers.

Primary change is exposing parseHtml on html_extractor to allow externally driving it rather than using a crawler.

Closes #537
chore(analyzer): update version number

Updating analyzer version to 0.11

Updated analyzer has a number of convenience methods that make it easier with code gen. No code changes needed.

Closes #527