get tests running on windows

I ran the tests on Windows and had some issues because of line endings changed by git.
I've added a function `normalizeLineendings` and moved it into a new base class.

There are still a few more issues because of the hard-coded path in `RepositoryTest`, but before I spend more time on this - is this a direction you'd like to go? I mostly work with C# these days and thus run some PHP projects on my windows box too..