Move all sources under atom/.

atom/app/atom_library_main.h

@@ -0,0 +1,17 @@
+// Copyright (c) 2013 GitHub, Inc. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef ATOM_APP_ATOM_LIBRARY_MAIN_
+#define ATOM_APP_ATOM_LIBRARY_MAIN_
+
+#include "base/basictypes.h"
+
+#if defined(OS_MACOSX)
+extern "C" {
+__attribute__((visibility("default")))
+int AtomMain(int argc, const char* argv[]);
+}
+#endif  // OS_MACOSX
+
+#endif  // ATOM_APP_ATOM_LIBRARY_MAIN_