EventListener, fire upload progress events. Bug 198595 and bug 312213, patch
by me for the cleanup and onreadystatechange and by Rob Adams
<readams@readams.net> for the upload progress changes, r=sicking, sr=peterv
git-svn-id: svn://10.0.0.236/trunk@196032 18797224-902f-48f8-a5cc-f745e15eee43