No error handling in ForexDataClient

[matjazbo]

ForexDataClient class, getQuotes function does not handle errors returned from the API.

For example, if quota has been exceeded, API returns something like:

{
  "error": true
  "message": "Your quota has been used fully.  Quotas reset at midnight EST. If you have any questions please email us at [email protected]"
}

but code ignores that and just tries to read quote data - which doesn't exist and PHP notices get thrown.