remove redundant configuration. IT for non-english-warnings had 1.4, but I don't see a reason for this value.

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1646979 13f79535-47bb-0310-9956-ffa450edef68
Add properties for source+target when used by maven-invoker-plugin.
Right now plugins are compiled with source/target 1.5, which is not supported by JDK9. However, we can test if 1.5 compiled plugins still work with a JDK9 runtime environment. You'll execute it like this:
mvn verify -Prun-its -Dinvoker.javaHome=%JAVA9_HOME% -Dinvoker.maven.compiler.source=1.6 -Dinvoker.maven.compiler.target=1.6

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1646983 13f79535-47bb-0310-9956-ffa450edef68
[maven-release-plugin] prepare release maven-antrun-plugin-1.8

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1646986 13f79535-47bb-0310-9956-ffa450edef68
[maven-release-plugin] prepare for next development iteration

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1646988 13f79535-47bb-0310-9956-ffa450edef68
Make verify-script JDK9 proof (hopefully they won't change the message...)

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1647008 13f79535-47bb-0310-9956-ffa450edef68