Use non deprecated way to add listener
Use portable way to create temp dir.
Replace deprecated addListener calls with addClickListener
Fire valueChangeEvent also when file is deleted after upload.
Revert "Fire valueChangeEvent also when file is deleted after upload."

This reverts commit fb09a92ceec0a7c07f3349593b98da291536492c.
Fire valueChangeEvent in setValue(), so that a event is also triggered
when an uploaded file is deleted.
implement add/removeValueChangeListener
Merge pull request #7 from dve/master

Minor style changes and ValueChangeEvent on file delete