TYPO3 Core

At the moment a lot of tests are skipped on windows environments. The main reasons are permissions, symlinks and shell exec commands. As symlinks are now working on Windows (if the user / group is allowed to create them, see http://superuser.com/questions/104845/permission-to-make-symbolic-links-in-windows-7) there is no reason to skip those tests. As you can only create valid symlinks on Windows (the target is checked for existence) the tests needed to be adjusted to take that into account.

Additionally some of the other tests don't need to be skipped either, as they mock all system specific calls (e.g. AbstractNodeTests).

For the other tests the message on skipping was updated to contain more information as to what causes them to be irrelevant on Windows.