Updated samples to explicitly call drawUI (updated ImGUI version), some code cleanup, removed no-longer necessary UI setup

Refs #496

examples/conservativeraster/conservativeraster.cpp

@@ -419,6 +419,8 @@ public:
 			vkCmdBindDescriptorSets(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipelineLayouts.scene, 0, 1, &descriptorSets.scene, 0, nullptr);
 			vkCmdDraw(drawCmdBuffers[i], 3, 1, 0, 0);
 
+			drawUI(drawCmdBuffers[i]);
+
 			vkCmdEndRenderPass(drawCmdBuffers[i]);
 
 			VK_CHECK_RESULT(vkEndCommandBuffer(drawCmdBuffers[i]));