update no key error to reflect the missing requirements
Merge pull request #8 from askmike/patch-1

update no key error to reflect the missing requirements
Merge pull request #7 from ralphtheninja/master

package.json
Made the currency configurable.

Now the currency of `BTCUSD` is not hardcoded anymore and can be set using the method `setCurrency`.
Merge pull request #9 from askmike/patch-2

Made the currency configurable.