Use PowerShell tests

[ForNeVeR]

As reported in our mail list by @ygra, Microsoft recently has published the test suite for PowerShell, maybe even targeting us as the audience for these tests, because I don't know who else could use them :)

So, someone need to research how to run these tests and start implementing environment for them to be run with Pash. Maybe we'll need to support Pester first of all.