- Modify the default HTML template to indicate that quirks mode is not supported
- Cleanup UserAgentGenerator.java, for consistency with DocumentModeGenerator.java
- Add two new configuration properties:

1. document.compatMode, to enumerate the permitted values {'CSS1Compat', 'BackCompat'} for
$doc.compatMode, by default:
<set-configuration-property name="document.compatMode" value="CSS1Compat"/>

2. document.compatMode.severity, to control the runtime check: IGNORE (no check), WARN (Development
Mode warning only), ERROR (runtime error). Current default:
<!-- The default value will be changed to 'ERROR' in a future release -->
<set-configuration-property name="document.compatMode.severity" value="WARN" />

Fixes issues: 6086, 6306

Review at http://gwt-code-reviews.appspot.com/1422816

Review by: jlabanca@google.com

git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@10204 8db76d5a-ed1c-0410-87a9-c151d255dfc7
6 files changed