READY: add signature script

Add a signature script which will poll someone's (the one we cared about :)) qq signature every 15 mins.

Has been tested against latest `hubot` (2.5.1) and `hubot-hipchat` (~2.5.1-1) under `node.js` (v0.8.17) and `coffee-script` (1.6.2), let me know if it's not working here.

Not sure where our current hubot robot is deployed now (seems not on that chuwa.us box), @29decibel or @garylin please help me deploy this script up :), thanks in advance.

```bash
git pull
npm install
sudo bluepill ...
```