Multi-module gradle project support

Issue from github https://github.com/mmatloka/arquillian-gradle-sample/issues/1:

Hi,

I'm very glad for your gradle resolver. However, we have multi project setup in which this code fails with an ArrayIndexOutOfBoundException

final GradleProject gradleProject = projectConnection.getModel(GradleProject.class);

    final File buildDir = new File(projectDir, "build");
    final File libsDir = new File(buildDir, "libs");
    final File result = libsDir.listFiles(new FilenameFilter() {
        @Override
        public boolean accept(final File dir, final String name) {
            return name.startsWith(gradleProject.getName());
        }
    })[0];

This is imho due to the fact that the gradleProject above holds the multi project but the arquillian tests are contained (and should be contained) in the sub project (*server). There the predicate will never be true and the [0] with end up in an exception.

I think you can either do a deep search to also get the sub project jars or more accurately resolve the project the tests are in. If you need help let me know.

Best,
Maik