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/icd/intel/buf.c b/icd/intel/buf.c
index f42571c..a145e5d 100644
--- a/icd/intel/buf.c
+++ b/icd/intel/buf.c
@@ -85,7 +85,7 @@
     struct intel_buf *buf;
 
     buf = (struct intel_buf *) intel_base_create(&dev->base.handle,
-            sizeof(*buf), dev->base.dbg, VK_DBG_OBJECT_BUFFER, info, 0);
+            sizeof(*buf), dev->base.dbg, VK_OBJECT_TYPE_BUFFER, info, 0);
     if (!buf)
         return VK_ERROR_OUT_OF_HOST_MEMORY;