Maven build rule execution framework

 Enforcer is a Maven build rule execution framework.
 Maven Enforcer Plugin provides goals to control certain environmental
 constraints such as Maven version, JDK version and OS family along with many
 more standard rules:
  * alwaysPass - Always passes... used to test plugin configuration.
  * alwaysFail - Always fail... used to test plugin configuration.
  * bannedDependencies - enforces that excluded dependencies aren't included.
  * evaluateBeanshell - evaluates a beanshell script.
  * requireReleaseDeps - enforces that no snapshots are included as
    dependencies.
  * requireReleaseVersion - enforces that the artifact is not a snapshot.
  * requireMavenVersion - enforces the Maven version.
  * requireJavaVersion - enforces the JDK version.
  * requireOS - enforces the OS / CPU Archictecture.
  * requirePluginVersions - enforces that all plugins have a specified version.
  * requireProperty - enforces the existence and values of properties.
  * requireFilesDontExist - enforces that the list of files do not exist.
  * requireFilesExist - enforces that the list of files do exist.
  * requireFilesSize - enforces that the list of files exist and are within a
    certain size range.
 Custom rules are easy to make with the maven-enforcer-rule-api.