Update to version 2.0.0

• Updated documentation.
• Move to virtualenv/pip based development.
• Move to Read The Docs for documentation.
• Use Travis CI for testing and releases.
• Use features of newer testfixtures in CheckerView.
• Python 3 compatibility.

PR: 245061
Submitted by: Miroslav Lachman <000.fbsd@quip.cz>