BGE is compilable by MSVC again

BGE is compilable by MSVC again

Compilation error was mostly caused by trying to use namespace std before it was
actually defined (e.g. before any include of stl header).
It's not actually good idea to use namespaces in header files -- it's really easy to
run into namespace conflicts and so. Resolved by not using "using namespace" in header
files and using full quality accessing to stl collections (e.g. std::vector).