Added shader material

[DanielAbalde]

Here is a basic implementation for shader material.

It can be extended once you pass this implementation, mainly to add new uniform types.

I think you have to implement your Script object first in order to be able to update uniform values since Render().

Sample file (is more a dev testing file that a sample file):
ThreePlus-Materials-11_Shader.zip

_{^{It has been a headache to synchronize my project with yours because I downloaded the project as a ZIP and your VS solution is inside a folder. I was able to fix it by re-downloading the project, this time with "Open with Visual Studio" and the cloning was successful. I've probably used a bad habit but it has worked for me so far. However when I copied and pasted my changes into the new properly cloned project, there was a formatting adjustment adding unnecessary spaces. Keep this in mind when reviewing the changes.}}