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/textoverlay/mesh.frag

@@ -0,0 +1,19 @@
+#version 450
+
+layout (location = 0) in vec3 inNormal;
+layout (location = 1) in vec2 inUV;
+layout (location = 2) in vec3 inViewVec;
+layout (location = 3) in vec3 inLightVec;
+
+layout (location = 0) out vec4 outFragColor;
+
+void main() 
+{
+	vec3 N = normalize(inNormal);
+	vec3 L = normalize(inLightVec);
+	vec3 V = normalize(inViewVec);
+	vec3 R = reflect(-L, N);
+	float diffuse = max(dot(N, L), 0.0);
+	float specular = pow(max(dot(R, V), 0.0), 1.0);
+	outFragColor = vec4(vec3(diffuse + specular) * vec3(0.25), 1.0);	
+}

data/shaders/glsl/textoverlay/mesh.vert

@@ -0,0 +1,35 @@
+#version 450
+
+layout (location = 0) in vec3 inPos;
+layout (location = 1) in vec3 inNormal;
+layout (location = 2) in vec2 inUV;
+
+layout (binding = 0) uniform UBO 
+{
+	mat4 projection;
+	mat4 model;
+	vec4 lightPos;
+} ubo;
+
+layout (location = 0) out vec3 outNormal;
+layout (location = 1) out vec2 outUV;
+layout (location = 2) out vec3 outViewVec;
+layout (location = 3) out vec3 outLightVec;
+
+out gl_PerVertex 
+{
+	vec4 gl_Position;   
+};
+
+void main() 
+{
+	outNormal = inNormal;
+	outUV = inUV;
+	gl_Position = ubo.projection * ubo.model * vec4(inPos.xyz, 1.0);
+	
+	vec4 pos = ubo.model * vec4(inPos, 1.0);
+	outNormal = mat3(transpose(inverse(ubo.model))) * normalize(inNormal);
+	vec3 lPos = mat3(ubo.model) * ubo.lightPos.xyz;
+	outLightVec = lPos - pos.xyz;
+	outViewVec = -pos.xyz;			
+}

data/shaders/glsl/textoverlay/text.frag

@@ -0,0 +1,13 @@
+#version 450 core
+
+layout (location = 0) in vec2 inUV;
+
+layout (binding = 0) uniform sampler2D samplerFont;
+
+layout (location = 0) out vec4 outFragColor;
+
+void main(void)
+{
+	float color = texture(samplerFont, inUV).r;
+	outFragColor = vec4(color);
+}

data/shaders/glsl/textoverlay/text.vert

@@ -0,0 +1,17 @@
+#version 450 core
+
+layout (location = 0) in vec2 inPos;
+layout (location = 1) in vec2 inUV;
+
+layout (location = 0) out vec2 outUV;
+
+out gl_PerVertex 
+{
+	vec4 gl_Position;   
+};
+
+void main(void)
+{
+	gl_Position = vec4(inPos, 0.0, 1.0);
+	outUV = inUV;
+}