* [sdl1][sdl1-net] Add new port for SDL v1.2.15 & SDL_net v1.2.8
* Version 1.2 is still required for building DOSbox
* [sdl1][sdl1-net] Revise to install to expected paths
* Headers go in include\ instead of include\SDL1
* Use updated .sln and .vcxproj files
* [sdl1] Modernize
