src: handle last event before exiting status threads

- Avoid 2 consecutive calls to uv_async_send when exiting the cardreader.cpp
  check status thread.
- Fix mutex unlock location in cardreader.cpp check status thread.

PR-URL: https://github.com/santigimeno/node-pcsclite/pull/46
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>

src/pcsclite.cpp

@@ -124,11 +124,6 @@ void PCSCLite::HandleReaderStatusChange(uv_async_t *handle, int status) {
     AsyncBaton* async_baton = static_cast<AsyncBaton*>(handle->data);
     AsyncResult* ar = async_baton->async_result;
 
-    if (ar->do_exit) {
-        uv_close(reinterpret_cast<uv_handle_t*>(&async_baton->async), CloseCallback); // necessary otherwise UV will block
-        return;
-    }
-
     if ((ar->result == SCARD_S_SUCCESS) || (ar->result == (LONG)SCARD_E_NO_READERS_AVAILABLE)) {
         const unsigned argc = 2;
         Local<Value> argv[argc] = {
@@ -145,6 +140,12 @@ void PCSCLite::HandleReaderStatusChange(uv_async_t *handle, int status) {
         Nan::Callback(Nan::New(async_baton->callback)).Call(argc, argv);
     }
 
+    // Do exit, after throwing last events
+    if (ar->do_exit) {
+        uv_close(reinterpret_cast<uv_handle_t*>(&async_baton->async), CloseCallback); // necessary otherwise UV will block
+        return;
+    }
+
     /* reset AsyncResult */
     delete [] ar->readers_name;
     ar->readers_name = NULL;