Speed up i18n generation by caching partial results.

Merged r5525-5527 from the 6/2 snapshot branch, modified with
review feedback.

Patch by: jat
Review by: fabbott


git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@5576 8db76d5a-ed1c-0410-87a9-c151d255dfc7
6 files changed