Release audit tool for sbt. See changelog.

This plugin is built for sbt 0.13.x and 1.x, and it is available as an auto plugin. To add this to your project, add the following to your build:
project/plugins.sbt
addSbtPlugin("org.musigma" % "sbt-rat" % "0.7.0")This adds two tasks: ratCheck and ratReport.
The first task will fail the build if the audit check fails.
The second task generates the audit report files (plain text and AsciiDoc).
Run sbt "^scripted" for sbt script tests.