Port Cytopia to emscripten

[SimplyLiz]

Port Cytopia to emscripten and host the build on our website.

I've already started working on this and pretty much is already done, but haven't commited the code changes yet.

Notes: I've started working on this on linux, but i couldn't get emscripten to work. On Windows, it worked instantly, but stopped working after a time because of a bug in emscripten in latest release.
I'll continue working on this once i have my new laptop set up.

See:
https://game.cytopia.net

SDL_mixer support is still missing.
The game crashes when save / load game is called. (Find out how we can open a browser save / load dialog)

[SimplyLiz]

I created a branch "emscripten" for the port.

To build it:

Activate emscripten SDK

~/.conan/data/emsdk_installer/1.39.6/bincrafters/stable/package/1492a59deb6efdf29776a5734de63fc5f5c58650/emsdk_env.shemsdk activate latest
source ~/.conan/data/emsdk_installer/1.39.6/bincrafters/stable/package/1492a59deb6efdf29776a5734de63fc5f5c58650/emsdk_env.sh
export PATH=~/.conan/data/emsdk_installer/1.39.6/bincrafters/stable/package/1492a59deb6efdf29776a5734de63fc5f5c58650:~/.conan/data/emsdk_installer/1.39.6/bincrafters/stable/package/1492a59deb6efdf29776a5734de63fc5f5c58650/node/12.9.1_64bit/bin:~/.conan/data/emsdk_installer/1.39.6/bincrafters/stable/package/1492a59deb6efdf29776a5734de63fc5f5c58650/upstream/emscripten:$PATH

emcmake cmake -DCROSSBUILD_EMSCRIPTEN=ON -DENABLE_AUDIO=OFF -DENABLE_ANGELSCRIPT=OFF -DENABLE_MOFILEREADER=OFF ../Cytopia