layers: INITIAL Changes to use new WSI swapchain extensions.

There are still some FIXME's that must be addressed, as well as fully
supporting the new entrypoints.  This patch serves as a basis for review and
further work with other Vulkan engineers.
diff --git a/layers/mem_tracker.h b/layers/mem_tracker.h
index 48d4f14..4416e6c 100644
--- a/layers/mem_tracker.h
+++ b/layers/mem_tracker.h
@@ -140,7 +140,7 @@
 
 struct MT_SWAP_CHAIN_INFO {
     VkSwapChainCreateInfoWSI             createInfo;
-    std::vector<VkSwapChainImageInfoWSI> images;
+    std::vector<VkSwapChainImagePropertiesWSI> images;
 };
 
 #ifdef __cplusplus