Added example using callbacks

src/v8test.erl

@@ -0,0 +1,14 @@
+-module(v8test).
+-export([run/0]).
+-include_lib("erlv8/include/erlv8.hrl").
+
+run() ->
+    application:start(erlv8),
+    {ok, VM} = erlv8_vm:start(),
+    Global = erlv8_vm:global(VM),
+    Global:set_value("callback",  erlv8_object:new([{"exec", fun (#erlv8_fun_invocation{}, []) -> myCallback() end}])),
+    erlv8_vm:run(VM,"callback.exec();").
+
+myCallback() ->
+    io:format("Hello from myCallback!~n", []),
+    ok.