#872
#880
fix for droup down items in TbButton
Update TbFileUpload.php

Add callbacks based on work by Szymon Dudziak.
Fix wrong site of the created button when using type "link"
Merge pull request #884 from bobnvic/master

Add callbacks to TbFileUpload
Merge pull request #886 from Tak0r/master

Fix wrong site of the created button when using type "link"