New UploadListener "uploadSend" event

Upload listeners can now get notified for the event that an upload
is started. While the "uploadStart" event in UploadProcessListener
does not allow user interface modifications because it runs outside of
user interface threads, this event does.
Fix IE 7 and IE 6 issues with downloads over ssl

Resolves #5
Merge branch 'hotfix/IE-ssl-downloads' of github.com:ceari/echo3filetransfer into stable-3.0.x
Merge branch 'feature/upload-send-events' of github.com:ceari/echo3filetransfer into stable-3.0.x