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/loader/wsi_lunarg.h b/loader/wsi_lunarg.h
index 02ff37e..57c2e62 100644
--- a/loader/wsi_lunarg.h
+++ b/loader/wsi_lunarg.h
@@ -34,15 +34,18 @@
         size_t*                                 pDataSize,
         void*                                   pData);
 
-void wsi_lunarg_register_extensions(
-        const VkInstanceCreateInfo*             pCreateInfo);
+void wsi_lunarg_create_instance(
+        struct loader_instance *ptr_instance);
 
 void *wsi_lunarg_GetInstanceProcAddr(
         VkInstance                              instance,
-        const char*                             pName,
-        bool*                                   enabled);
+        const char*                             pName);
 
 void *wsi_lunarg_GetDeviceProcAddr(
         VkDevice                                device,
-        const char*                             pName,
-        bool*                                   enabled);
+        const char*                             pName);
+
+VkResult wsi_lunarg_CreateSwapChainWSI(
+        VkDevice                                device,
+        const VkSwapChainCreateInfoWSI*         pCreateInfo,
+        VkSwapChainWSI*                         pSwapChain);