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"
Fix TbEditableColumn base class error.
fix tb button type link to render link
#887
#891
fixing build
#893
#882
fixing build error
#883
#873, #875
fix
#867
changelog
Update TbButton.php

for PHP < 5.4
#900
fixing a gii enum generation bug