Add support for Bitdeli

Hi!

Here's a service provider integration for our [brand new tracking library](https://github.com/bitdeli/bitdeli-tracking-js). You can check out the API reference at https://bitdeli.com/docs/javascript-api.html.

I put this together based on previous pull requests in your repo as well as some of your latest commits. I'm happy to make any changes if something doesn't look right.

What's the process for adding new providers to your hosted solution?

Thanks for the awesome initiative in building analytics.js!

Best,

Jyri Tuulos
Bitdeli