GRAILS-10090 - change default view path for namespaced controllers

If a controller defines a namespace, use the namespace as the default top level piece of the view path instead of the controller name.
GRAILS-10090 - improve view rendering for namespaced controllers

The default view path for namespaced controllers will now be grails-app/views/controllerNamespace/controller/view and if that does not exist the fallback is the previous default of grails-app/views/controller/view.

Squashing commits from local branch to eliminate the evolution and later elimination of complexity.  This ends up being fairly simple.
2.3.9.BUILD-SNAPSHOT
don't add the withFormat method if it already exists
The default request method for mock requests should be GET

Related to commit 4e6359df6b6196eeec2fc129b94c1cb07380917e
different approach for checking the existence of a method

This is more consistent with the version of this class which is currently on the master branch.
Merge branch '2.3.x'

Conflicts:
	build.gradle
	build.properties
	grails-plugin-testing/src/main/groovy/grails/test/mixin/web/ControllerUnitTestMixin.groovy
	grails-test-suite-uber/src/test/groovy/grails/util/GrailsUtilTests.java
	grails-test/src/main/groovy/org/codehaus/groovy/grails/plugins/testing/GrailsMockHttpServletRequest.groovy