Add mac support to the FF50 plugin and package a candidate xpi.

Review at http://gwt-code-reviews.appspot.com/1467809

Review by: codefu@google.com

git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@10402 8db76d5a-ed1c-0410-87a9-c151d255dfc7
8 files changed