Move shaders into glsl and hlsl directories

Move `data/shaders` to `data/shaders/glsl`
Move `data/hlsl` to `data/shaders/hlsl`

Fix up shader paths in the cpp files to point to the new glsl location.

`data/shaders/hlsl/compile.py` still overwrites the glsl .spv files (for
now).

Issue: #723

data/shaders/stencilbuffer/toon.frag

@@ -1,30 +0,0 @@
-#version 450
-
-layout (binding = 1) uniform sampler2D samplerColorMap;
-
-layout (location = 0) in vec3 inNormal;
-layout (location = 1) in vec3 inColor;
-layout (location = 2) in vec3 inLightVec;
-
-layout (location = 0) out vec4 outFragColor;
-
-void main() 
-{
-	vec3 color;
-	vec3 N = normalize(inNormal);
-	vec3 L = normalize(inLightVec);
-	float intensity = dot(N,L);
-	if (intensity > 0.98)
-		color = inColor * 1.5;
-	else if  (intensity > 0.9)
-		color = inColor * 1.0;
-	else if (intensity > 0.5)
-		color = inColor * 0.6;
-	else if (intensity > 0.25)
-		color = inColor * 0.4;
-	else
-		color = inColor * 0.2;
-	// Desaturate a bit
-	color = vec3(mix(color, vec3(dot(vec3(0.2126,0.7152,0.0722), color)), 0.1));	
-	outFragColor.rgb = color;
-}