display: width and height instance variables
Remove SingletonD
Merge branch 'display-refactor' into zope.interface-display
IDisplay
display using ZCA
Merge branch 'zope.interface' into zope.interface-display

Conflicts:
	letsencrypt/client/client.py
	letsencrypt/scripts/main.py
Merge branch 'zope.interface-display' of git://github.com/kuba/lets-encrypt-preview into kuba-zope.interface-display
Make necessary fixes to pull request
git push origin masterMerge branch 'kuba-zope.interface-display'