adds vendor directory

vendors dependencies in standard `vendor` directory, managed by glide

vendor/github.com/mattn/go-pointer/example/example.go

@@ -0,0 +1,13 @@
+package example
+
+/*
+void *pass_pointer(void* p) {
+  return p;
+}
+*/
+import "C"
+import "unsafe"
+
+func PassPointer(ptr unsafe.Pointer) unsafe.Pointer {
+	return C.pass_pointer(ptr)
+}