Improve testing framework

Replaced Criterrion with CMock. Added few tests, currently not working
properly. Random test upgrades.

graphics/shaders/solid_objects.frag

@@ -14,5 +14,5 @@ layout(location = 0) out vec4 outColor;
 
 void main() {
     vec4 texturePixels = texture(texSampler[instanceTextureId], fragTexCoord);
-    outColor = vec4(fragColor * texturePixels, texturePixels.a);
+    outColor = vec4(fragColor * texturePixels.rgb, texturePixels.a);
 }