Fix for compatibility of solution file
Fix for ThreadLocal

ThreadLocal will cache exceptions as the documentation says.
Also added protection against recursion in the value factory of the
ThreadLocal.
Fixes for ManualResetEventSlim
SpinLock fixes
Clean up

Unused variables and stuff
Published ThreadLocal.Values and clean up
Fixes to run tests againts different .NET

ThreadLocal<T>.Values does not exist in .NET 4.0 - but it is backported
from .NET 4.5 to .NET 2.0 up to .NET 3.5.

This means that ThreadLocal<T>.Values works in every .NET except .NET
4.0

If need a solution that works in every .NET use
Theraot.Threading.TrackingThreadLocal<T> - it is a drop in replacement.