Enable generator result caching, by default.

This initially will allow caching for ClientBundle and RPC generators.  Other generators can be updated to support caching.

The -XenableGeneratorResultCaching flag is now redundant, but it is still
allowed.  It should eventually be phased out.

To allow diabling caching if needed, the system property
"gwt.disableGeneratorResultCaching" is now available.

Review at http://gwt-code-reviews.appspot.com/1467808


git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@10411 8db76d5a-ed1c-0410-87a9-c151d255dfc7
6 files changed