Update FFI.Library to use FFI.call

lib/ffi/library.ex

@@ -14,16 +14,13 @@ defmodule FFI.Library do
 
   defmacro attach_function(name, arguments, return_type) do
     quote do
-      def unquote(name)(pid, params) do
-        args = {unquote(name), params}
+      def unquote(name)(params) do
+        definition = {ffi_lib,
+                      unquote(name),
+                      unquote(arguments),
+                      unquote(return_type)}
 
-        GenServer.call(pid, args)
-      end
-
-      def handle_call({unquote(name), params}, _from, state) do
-        IO.puts ffi_lib
-        a = IO.puts(params)
-        {:reply, a, state}
+        FFI.call(definition, params)
       end
     end
   end