Add tests for invalid MFE arguments
Handle invalid MFE arguments
Merge pull request #2333 from yakky/feature/fix_2250

Attach placeholder to model if no placeholder found
Document adding PlaceholderField to an existing model
Merge pull request #2319 from FinalAngel/develop

More frontend fixes
Merge pull request #2334 from yakky/feature/add_docs_2250

Document adding PlaceholderField to an existing model
Fixing #1649 - NoReverseMatch raised if apphook doesn't exist

Some apps, like cmsplugin-zinnia and cmsplugin_news will raise NoReverseMatch when trying to generate their menus before an apphook is installed. In sampleapp this is solved by adding a try-except like the one in this commit. Placing the try-except in django-cms instead of inside every app would simplify the process of writing plugins and avoid some confusing 500-errors for new users trying to install plugins.
Add messages when apphook raises exception in menu
Limits messages to staff users only
Reword the error message and log the error.
That was a stupid error
Fix whitespaces
Merge pull request #2332 from yakky/feature/frontend_models_enh

Sparse enhancements for MFE
use correct namespace
Fix formatting error in MFE template
Merge pull request #2336 from yakky/feature/fix_mfe_space

Fix formatting error in MFE template
modal popup: jquery hide function breaks ckeditor on firefox
defered rendering working
Refactored get_site_id into an utility function.
get_site_id was implemented twice, once in templatetags/cms_tags as get_site
and once in utils/i18n.py as get_site_id.
This is a prerequisite for multisite installations.
fix aligning