Let events from all magento areas to fire during unit tests

Previously we only loaded the 'global' event namespace which meant if you defined an event under, for example, <adminhtml> they would not be loaded and therefore not fire during a TestCase.

This patch ensures when setting up a new testcase, all event areas are loaded.

I have also removed the core tests being automatically symlinked by modman/composer, because they are broken for all but the most vanilla install stores (and I'm not sure if they even work under 1.8 actually...that's a todo).