Merge remote-tracking branch 'origin/master'
Implement a specialized version of IConcurrencyAbstractionLayer, in order to allow Rx tests to use a predefined TestScheduler instance by default.
Change the TestScheduler property to be a lambda instead, so that we can leverage ThreadLocal<> to retrieve the value.
Merge remote-tracking branch 'origin/master' into IMockVerifyStartsCountingFromCallToBecause

Conflicts:
	solution/src/app/Testeroids/ContextSpecificationBase.cs
	solution/src/app/Testeroids/Testeroids.csproj
	solution/src/app/Testeroids/packages.config