Added .datepicker class

I added a class to the selector. In one view may be more than one datepicker.
fix for #2422. Change the dataProcessor.toDataFormat function which is sensible to the editor enterMode, causing this issue.
Adding Cancel URI to edit/create page type field.
Changed blog category check_title method reference to check_slug
Keep from breaking blog intro image insertion as described in #2391
Merge pull request #2424 from dresfdez/hotfix/2422

fix for #2422. Issue with tags inside image src
Merge pull request #2419 from beruniu/patch-1

Added .datepicker class
Merge branch '2.2/develop' of github.com:pyrocms/pyrocms into 2.2/develop
Allow tags on the pages default body field.

This is the reason new installs don't have tags parsing on the contact page lately.