Added ManualResetEventSlimTests
Added SpinLockTests
Added ThreadLocalTests
Initial fix for ThreadLocal
Fixed conditional compilation
WaitHandleConsistencyTest doesn't work on .NET

I do not know if there is something wrong with ManualResetEventSlim in
.NET - yet aparenty Mono has decided on a more strict behaviour than
Microsoft.
Added guard in MultipleReferenceToValueTest

Because StackOverflow is nasty enough - yet I still want to fix this -
but can't fix Microsoft's code.
Marked other tests that fail against .NET 4.0

These are Microsoft's fault