LUN-1507 : Fix checkboxes and scroller
-Fix checkboxes IE, FF, etc
-Fix toggles for IE8/9
-Fix DateTimeWidget with initial start publication date in IE8
Merge pull request #6 from laurafeier/LUN-1507

Browser specific fixes
Added author model to allow users to add authors that are not django users
Merge branch 'master' of github.com:laurafeier/django-cms-blogger
Refactored code for blog categories creation.
Fix IE8 tinyMCE initializing after window.load event; use tinyMCE's own init event
Fix text area resize
Merge pull request #8 from laurafeier/LUN-1507

Fix IE8 tinyMCE initializing after window.load event
Added slug validation for entries;
When an entry queryset gets deleted all the poster images will get deleted from storage;
Moved entry categories logic from admin to entry form.
Merge branch 'master' of github.com:laurafeier/django-cms-blogger
Merge with master.