Allow @Input on "complex type" attributes

My specific experience was with custom beans being used as the type of an attribute marked as @Input. The belief is any "complex type" will cause the same issue.

An example can be found in the jDocBook plugin code. One such example is the getFormat() method in the RenderTask ( http://github.com/gradle/gradle-jdocbook/blob/master/src/main/groovy/org/jboss/gradle/plugins/jdocbook/RenderTask.java ). You can see how I needed to "flatten" out the bean attributes in order to get it working.