changed from new instantiation to event
removed rerendering of header
do not remove header
clean bottom content before rerendering
show back button
fixed component leak
hide and show the header
fixed back button
Merge branch 'develop' into feature/tabs-refactoring

Conflicts:
	Resources/public/dist/app.min.1408541157155.css
	Resources/public/dist/app.min.css
	Resources/public/dist/app.min.js
	Resources/public/js/aura_extensions/sulu-content.js
	Resources/public/js/components/header/main.js
	Resources/views/Admin/index.html.dist.twig
Merge pull request #156 from sulu-cmf/feature/tabs-refactoring

[ENHANCEMENT] Change header instead of recreating everytime