First commit of the event view ajaxification

- pagination of the attribute index within the event view
- add attributes in a pop-up window
- instantly refresh attributes
Two missing view-elements from the previous commit added
Next step in the ajaxification
Next step in the ajaxification of the event view

- users can now edit all fields in an attribute whilst on the event page

- issues left to fix:
	- tag changes after an attribute change run into CSRF protection
	- batch add not handled gracefully yet
	- going back to the event view and editing a field gives users an error message over the CSRF protection - instead, silently check if the page is loaded in a dirty way and refresh the ajax fields silently
	- quickadd of attributes still missing
next step in the ajaxification

- multiselect / multidelete
- some additional UI changes for the event view
Rework of the way the ajax editing works

- forms are now dynamically pulled onclick
- performance greatly enhanced
- solves the issues with the CSRF protection kicking in if the user edits a field after using the back button
Further work on the ajaxification

- mass deletes / mass edits

- tagging now done via ajax

- also, several small unrelated issues fixed
Ajaxification of the event page done also, replaced histogram in memberslist

- AJAX requests now also respond with a small message at the bottom of the page, notifying the user of the result
- The following actions work now on the event page via ajax:

1. Add / remove tags
2. quick edit any attribute field if eligible
3. quickly create a proposal of any attribute field if not eligible to edit
4. popover attribute creation (also works with batch add)
5. popover proposal creation (also works with batch add)
6. delete attributes
7. accept/discard proposals
8. mass edit / delete attributes

Also, replaced the old memberslist, with a small lightweight css/js based one.
Clearer disctinction between proposals that belong to an attribute and proposals to an event
Merge branch 'develop' into features/ajaxification

Conflicts:
	app/View/Elements/img.ctp
Merge branch 'features/ajaxification' into develop