Switched from currency and asset to assetpairs.
Some URLs changed, cleanups (all URLs end on /).
Adjustments after XWrap changes, added Account.

Adjusted the API after changes were made on the service, added
an Account object that deals with the URLs that require logiAdjustments after XWrap changes, added Account.

Adjusted the API after changes were made on the service, added
an Account object that deals with the URLs that require loginn
Added apikey, enabled and available to Backend.
Updates after API changes, interactive prompt.
Added missing 'withdraw_limits()' method.