extensions: begin changes for extension support

This patch starts restructuring the various components
(loader, driver, layers, etc.) to support global and
device extensions. Require GetProcAddr to access the
extension functions and related support.
diff --git a/layers/draw_state.h b/layers/draw_state.h
index a7351bb..d56f2db 100644
--- a/layers/draw_state.h
+++ b/layers/draw_state.h
@@ -122,7 +122,8 @@
 } BUFFER_NODE;
 
 typedef struct _DYNAMIC_STATE_NODE {
-    VkDynamicStateObject    stateObj;
+    VkObjectType                objType;
+    VkDynamicStateObject        stateObj;
     GENERIC_HEADER*             pCreateInfo;
     union {
         VkDynamicVpStateCreateInfo vpci;