Add light-weight Map class

[Argoday]

Add light-weight Map::Map class to reduce dependence on std::map which is only used by Data::DataManager however std::map adds too much to DLL size

[Argoday]

I eventually decided against making this change. There is no point in duplicating fundamental stl containers just yet. Later if code size becomes a priority then this will need to be revisited - however when compiling statically this isn't much of a real issue.