Fixes a problem in JavaScript code generation where we were sometimes using JavaScript keywords as field names in a JSON object construction.  For example:

[false:0, true:1, foo:3]

We now quote keywords in this context.

["false":0, "true":1, foo:3]

Review by: mmendez


git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@1542 8db76d5a-ed1c-0410-87a9-c151d255dfc7