Documentation for release 2.1.2.
Merge tag '2.1.2-doc' into gh-pages

Conflicts:
	.buildinfo
	async.html
	config.html
	error.html
	genindex.html
	index.html
	protocol.html
	py-modindex.html
	search.html
	searchindex.js
	sync.html

Documentation for release 2.1.1.