[MTOOLCHAINS-8] improved code and javadoc

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1635873 13f79535-47bb-0310-9956-ffa450edef68
[MTOOLCHAINS-9] upgraded to Maven 2.2.1 compatibility

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1635879 13f79535-47bb-0310-9956-ffa450edef68
improved documentation

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1635882 13f79535-47bb-0310-9956-ffa450edef68