Merge pull request #4 from alendit/master

IFrame für Authoring entfernt
Grappelli added to requirements
Login and registration fixed
Adding styles for registration form
integration of form magic with https://github.com/harvesthq/chosen
minify css files
removed some files
changed some markup
Merge branch 'dev-chosen'
Merge branch 'master' of github.com:DesignerTUM/creyoco

Conflicts:
	src/exedjango/exeapp/templates/exe/mainpage.html
fixing typo bug in mainpage.js
improve markup
Some work on websiteexport.py
Download links refactored
A very basic version of preview generation
Removed reference to handle_export
Basic preview bound to url
Preview links handling fixed
Fixed style selection
Missing imaged replaced by dummies