Started work on descriptor indexing example

Refs #583

data/shaders/descriptorindexing/descriptorindexing.frag

@@ -0,0 +1,15 @@
+#version 450
+
+#extension GL_EXT_nonuniform_qualifier : require
+
+layout (set = 0, binding = 1) uniform sampler2D textures[];
+
+layout (location = 0) in vec2 inUV;
+layout (location = 1) flat in int inTexIndex;
+
+layout (location = 0) out vec4 outFragColor;
+
+void main() 
+{
+	outFragColor = texture(textures[nonuniformEXT(inTexIndex)], inUV);
+}