Removed all extraneous copies by adding the class 'InterfaceReg' which will construct a new interface, and link it to the engine's static register. The Source Engine macro 'EXPOSE_INTERFACE_FN' will help utilizing this. The game module from the plugin is not obtained through the process environment block, so the executable is no longer sensitive to names.
Added all public headers to CMake projects, also moved some files around in the public directory. Translation units have been moved to the libraries that were responsible for implementing them, as this game is monolithic.
