[Thread] Fix: WaitableBool::operator=() should lock the whole function.
(minor) Some feature not supported in VC2012 are now available in VC2013.

- Some comments refered to VC2012 are now changed to VC2013.
[VC] Minimun Visual C++ version are now 2013.
(refactoring) Prefer C++11 initializer_list.