Update README (this is 18.0.0)

* Add calver versioning scheme
* Fix bootstrap version
* Update changelog

This is 0.13.0

This is 0.12.0

This is 0.11.1

This is 0.11.0

Fix calls to _run_flask_command

This is 0.10.0

This is 0.9.0

Update changelog

Update changelog for 0.7.0