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/glsl/skeletalanimation/texture.frag

@@ -0,0 +1,28 @@
+#version 450
+
+layout (binding = 1) uniform sampler2D samplerColorMap;
+
+layout (location = 0) in vec2 inUV;
+layout (location = 1) in vec3 inNormal;
+layout (location = 2) in vec3 inViewVec;
+layout (location = 3) in vec3 inLightVec;
+
+layout (location = 0) out vec4 outFragColor;
+
+void main() 
+{
+	vec4 color = texture(samplerColorMap, inUV);
+
+	float distSqr = dot(inLightVec, inLightVec);
+	vec3 lVec = inLightVec * inversesqrt(distSqr);
+
+	const float attInvRadius = 1.0/5000.0;	
+	float atten = max(clamp(1.0 - attInvRadius * sqrt(distSqr), 0.0, 1.0), 0.0);
+
+	// Fake drop shadow	
+	const float shadowInvRadius = 1.0/2500.0;
+	float dropshadow = max(clamp(1.0 - shadowInvRadius * sqrt(distSqr), 0.0, 1.0), 0.0);
+	
+	outFragColor = vec4(color.rgba * (1.0 - dropshadow));
+	outFragColor.rgb *= atten;
+}