Remove ant dependency and update exception handling

[cherylking]

Preparation to remove all references to Maven 2.x APIs (org.codehaus) related to #1651.

1. Added our own AntTaskFactory to replace org.codehaus.mojo.pluginsupport.ant.AntHelper.
2. Changed all goal implementations to throw MojoExecutionException as a precursor to having AbstractLibertySupport extend org.apache.maven.plugin.AbstractMojo instead of org.codehaus.mojo.pluginsupport.MojoSupport.
3. Moved code from doExecute methods into their own method that throws MojoExecutionException in order to identify all other exceptions that need to be caught and wrapped in a MojoExecutionException. The protected void doExecute() throws Exception methods will get replaced by @Override public void execute() throws MojoExecutionException once the inheritance is changed.
4. Changed all references to the log variable to use getLog() instead. Modified CommonLogger to instantiate a org.apache.maven.plugin.logging.SystemStreamLog if no logger was available when instantiated.

[mattbsox]

Looks good!