Integration: QR code DONE!

bugs to fix:
- nexus 7 preview resolution low
- onPause called without reason in captureActivity
- button clicks should have background highlight as feedbacks so user
knows not to click twice
- 未找到讯飞语音服务 alert dialog -> pressed 安装 but nothing happens
- toasting [TTSActivity... error
- in ArticleActivity, article title text too big on nexus s phone, don't
know how to adjust volume (volume key is adjusting ringtone volume
instead of T2S playback volume)