Fix build

[Kermalis]

This fixes the shader not working and also the build not working.

• The build gets placed at out/build/x64-Debug/ (for me), so the root directory is actually 3 directories up.
• The shader wasn't working because zTile is not a float, so using mod with 8.0 wouldn't compile for me. Needed to cast it
• This closes Build failed. Error C2593 on scene.cpp #36 as well because of some json casting error. Explicitly calling get with a string fixes it.
• This fixes With non-16:9 screen aspect ratios, the lights are no longer properly rendering #42

I'm also in the process of porting this engine to C#, with full credit to this repo and the assets used in it. I am not going to port some stuff due to different reasons.
Edit: It's basically done if you're curious: https://github.com/Kermalis/HybridRenderingEngine-CS
This is an awesome project :)

[Angelo1211]

Hi, I'm not currently accepting pull requests for this project as I don't have the time to manage it.

Thanks for your kind words and congrats, your C# port looks awesome :) !

[azer89]

Thanks for the PR. Eventhough it's closed, I was able to fetch it using this command:

git fetch origin pull/37/head:master