added requests package to easys rest api debugging
updated gitignore
renamed adapters.py to propertysheets.py
added cstruct method to ProperySheet
use interfaces to set permssions
initial rest api to create/modify content elements

Signed-off-by: Joscha Krutzki <joka@jokasis.de>
Merge branch 'zodb_substance_d' of github.com:adhocracy/adhocracy-3 into zodb_substance_d

Conflicts:
	.gitignore