Minor changes on project.clj

Set version to 1.6.0

Increment version to 1.5.1.

Update version on README.adoc file.

Set version to 1.4.0.

Set version to 1.3.0.

Set version to 1.2.2

Update doc, changelog and set version to 1.2.1.

Set version to 1.2.0.

Set version to 1.1.0.