Changed all of the tests that used GetSpecialFolder to use a new TestDirectory class that takes care of creating and deleting a directory for testing.
Removed obsolete SetAndRestoreCurrentDirectory  test
Commented out the line in the test harness ConsoleRunner that suppresses the result reporting in favour of the TeamCity reporting so that we will always find results in the build logs.
This should fix the failures for the TeamCity builds around the NotEmptyDirectory() test.
Merge pull request #192 from nunit/fix-directoryinfotests

Fix for occasionally failing tests that use GetSpecialFolder