In case other projects may use these header files, we added
them into API/Internals.

* ComputationGraphAlgorithms.h was moved from Source/ComputationNetworkLib

* PrimitiveOpType.h and EvaluatorWrapper.h were moved from Source/CNTKv2Library

* PrimitiveFunctionAttribute.h was extracted from PrimitiveFunction.h. It contains
  a new class PrimitiveFunctionAttribute which is the collection of all attribute
  names for PrimitiveFunction.

  This change actually had a subtle side-effect. We had a global static variable
  s_stateAttributes that depended on PrimitiveFunction::AttributeNameRngSeed and
  PrimitiveFunction::AttributeNameRngOffset. After we moved those static
  attribute-variables into another translation unit, s_stateAttributes can be
  initialized with empty wstring, because PrimitiveFunctionAttribute::AttributeNameRngSeed
  PrimitiveFunctionAttribute::AttributeNameRngSeedOffset were initialized after
  s_stateAttributes. Note that the initialization order of global static variables
  is not well-defined cross translation units. To fix the issue, we also moved
  s_stateAttributes into PrimitiveFunctionAttribute class, and renamed it to
  s_rngStateAttributes. I think it's reasonable to consider s_rngStateAttributes
  to be part of the PrimitiveFunctionAttribute class.

* PrimitiveFunction.h was moved from Source/CNTKv2Library