dev manual: Clean up theming chapter
Split HTML into three targets

 - doc.owncloud.org: make doc-org
 - doc.owncloud.com: make doc-com
 - release documentation: make release
Documentation moved to doc.ownloud.org, adjust theme
Merge remote-tracking branch 'origin/stable45'

Conflicts:
	developer_manual/conf_release.py
	user_manual/conf_release.py