Just load stubs and mocks from tests/jasmine/server/unit/ directory for Server Unit Test mode.

This is a breaking change. When you have stubs in a parent directory please move them to the
testing mode directories where the stubs should get loaded.
You can also use symlinks to use on stub in more then one mode.
Start FileCopier in Meteor.startup to maybe fix a rare copy error
Updates test-app and adds basic test and stub to all modes