Bitcoin Average Price

[shayanb]

fetch the bitcoinaverage.com CAD price instead of different exchanges.

Suggested API call:
https://api.bitcoinaverage.com/ticker/global/CAD/

{
  "24h_avg": 432.81,
  "ask": 429.42,
  "bid": 428.71,
  "last": 429.16,
  "timestamp": "Wed, 03 Dec 2014 23:04:35 -0000",
  "volume_btc": 592.22,
  "volume_percent": 1.32
}

I used the "24h_avg" price in Cafe Aunja at first but because of the price volatility I switched to "bid" price to prevent potential losses

[systemzax]

Changes have been pushed. Please review. Let's be careful because there seems to be some code redundancy in public/js/calculator.coffeescript, some of this seemingly redundant code is referencing the previous data structure, although it didn't seem to cause problems.