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/tessellation/passthrough.tesc

@@ -0,0 +1,24 @@
+#version 450
+
+layout (vertices = 3) out;
+
+layout (location = 0) in vec3 inNormal[];
+layout (location = 1) in vec2 inUV[];
+
+layout (location = 0) out vec3 outNormal[3];
+layout (location = 1) out vec2 outUV[3];
+
+void main(void)
+{
+    if (gl_InvocationID == 0)
+    {
+        gl_TessLevelInner[0] = 1.0;
+        gl_TessLevelOuter[0] = 1.0;
+        gl_TessLevelOuter[1] = 1.0;
+        gl_TessLevelOuter[2] = 1.0;
+    }
+
+    gl_out[gl_InvocationID].gl_Position = gl_in[gl_InvocationID].gl_Position;
+	outNormal[gl_InvocationID] = inNormal[gl_InvocationID];
+	outUV[gl_InvocationID] = inUV[gl_InvocationID];	
+}