ICE-6204 fixed the following issues: submitting the last selected file twice in FF; 'Add files' button not working after uploading files; 'Cancel upload' not correctly clearing the input type=file elements; and, re-uploading files every time 'Start upload' was clicked

git-svn-id: http://anonsvn.icesoft.org/repo/icefaces3/trunk/icefaces@38258 1de00972-ac04-4911-a46b-06793c8d78d9