[test]modify html5 test case
modify native mode test build moudle
[test] classify test case for automatic_tests and manual_tests
[test] Add test case for file dialog
Merge pull request #650 from owenc4a4/test

[Test] classify test case and test case for file dialog
bump version to 0.5.0
[README] update for 0.5.0
[API] Support for desktop keyboard hot key. Part of #200.

1. Add method registerGlobalHotkey and unregisterGlobalHotkey in gui.App.
2. Hotkey object implementation both js and C++ code.
3. The implementation on Windows.
[API][GTK] Use Xlib to implement global hotkey. Part of #200.

1. Use XGrabKey and XUngrabKey to implement global hotkey.
2. Refactor the code for better cross-platform.
[API][WIN] Move the HotKeyHandler to the hotkey_handler_win.cc. Part of #200.