#2022 - Fix handling of watermark dialog errors.
- admin_watermarks: changed header at end of form_add() from text/html to text/plain
- admin_watermarks: added header at end of form_edit() and form_delete() just like form_add() (currently omitted)
- admin_watermarks/gallery.dialog.js: removed unnecessary encode/decode workaround
Merge pull request #170 from shadlaws/fix_2022

#2022 - Fix handling of watermark dialog errors.