[ML] A MSVC friendly alternative to MathLib::pow().
Replace constexpr with const.
Correct linking errors for VS compiler/WIN32.
[ML] Move Face/Cell implementations in header file.
Revert "[ML] Move Face/Cell implementations in header file."

This reverts commit 14cdf0c6fd7edb7de0f3e026ca2aadd01a55f9d5.
Merge pull request #513 from endJunction/MathLibMSVCPow

Math lib msvc pow