Add 'Edit' title in candidate list view for editors

Separates more clearly the list details from the edit controls.
Allow filtering question by entity in admin

Also translate "entity".
Merge pull request #327 from danielhers/question-admin-filter-entity

Allow filtering question by entity in admin #323
Merge pull request #326 from danielhers/candidate-list-edit-title

Add 'Edit' title in candidate list view for editors
correct wrong usage of QuerySet.only()
add link to edit list details for candidates from edit profile, fix #319
more improvements to q&a admin, fix #323
remove population per candidate from entity stats, fix #312
fix #190
improve candidate list display
#318 Allow candidates to add links to their profile

The extra fields in the edit_profile form are displayed if the user is a
candidate. When the form is saved, the links are added to the candidate
using the generic foreign key in the Link model.
Move link fields to the end of edit_profile form
Show candidate links in public profile
Fix icon paths and add missing icons

Also use object_links to display them, and move them to be below the
candidate picture and description.
Use icons from Open Knesset rather than different ones
fix icons
prevent problems in profile page when is_candidate has 0 or 2 lists
fix bug with candidate removal when he is listed in two lists for some reason