Fix issue 10; based on contributions from Cory Stevens.

Use mimes.sort(true, new QualityComparator()) instead
of deprecated mimes.sort(new QualityComparator()) in
MediaTypeParser.

Add multiple improvements contributed by Cory Stevens
(https://github.com/corystevens) to make it easier to
upgrade the test application to Grails 2.4.x, including:

Replace CommonsClientHttpRequestFactory dependency with
HttpComponentsClientHttpRequestFactory.

Fix several spock tests that had incorrect test names
(copy/paste errors).

Remove use of org.apache.commons.lang.UnhandledException
in all tests.

Additional changes:

Update plugins to Grails 2.4.x compatible versions.

Update README-TESTING for Grails 2.4.x.
Update version to 0.9.1.