split of mimetype detection code from OC_Helper, adding the option for apps to register additional mimetype mappings
add the option to have templates for newly created files
add template for html files
use ===
actually register html template
Merge branch 'master' into mimetype-defaults

Conflicts:
	apps/files/ajax/newfile.php
communicate size of newly created file back and update UI
Merge pull request #4339 from owncloud/mimetype-defaults

Add the option to provide templates for newly created files