coinbase.go
func (c Client) RequestMoney(params *TransactionParams) (*transactionConfirmation, error) {
	return c.transactionRequest("POST", "request_money", params)
}
func (c Client) RequestMoney(params *TransactionParams) (*transactionConfirmation, error) {
	return c.transactionRequest("POST", "request_money", params)
}
// RequestMoney from either a bitcoin or email address