misc: bump header version to 170

This is version of header included in the provisional spec release
branch: release_provisional_I_20150910
diff --git a/include/vulkan.h b/include/vulkan.h
index 01cbfec..5f1972f 100644
--- a/include/vulkan.h
+++ b/include/vulkan.h
@@ -41,7 +41,7 @@
     ((major << 22) | (minor << 12) | patch)
 
 // Vulkan API version supported by this file
-#define VK_API_VERSION VK_MAKE_VERSION(0, 169, 0)
+#define VK_API_VERSION VK_MAKE_VERSION(0, 170, 0)
 
 
 #if defined(__cplusplus) && (_MSC_VER >= 1800 || __cplusplus >= 201103L)