Mozillians + Bugzilla server side implementation

Uses the Mozillians and BZ API to get the user data, as per discussed and stores it in `stats.json`.

* `install.sh` prepares the required files. It expects Node.js to be pre-installed.
* I repeat again. Do not merge this. It changes the users.json file and hence the current HTML code will fail to render. We should merge this to a separate branch (other than `gh-pages`), and collaboratively work until its ready.