uppAliasOnly is deprecated; use useAlias

[judgej]

It's used in a few places, so needs to be handled differently.

     * @var string value to request a card alias only (uppAliasOnly data item)
./src/Interfaces/Constants.php
        $data[] = $this->getAmountInteger() ?: 'uppAliasOnly';
./src/Message/AbstractRequest.php
            $data['uppAliasOnly'] = Gateway::CARD_ALIAS_ONLY;
./src/Message/AbstractRedirectRequest.php

The new useAlias is also used, so it may well be covered, but we need to be sure:

                $data['useAlias'] = Gateway::USE_ALIAS;
./src/Message/AbstractRedirectRequest.php
            'useAlias'   => 'yes'
./src/Message/TokenizeRequest.php
            'useAlias' => 'yes',
            'useAlias' => 'yes',
./tests/Message/TokenizeRequestTest.php

[judgej]

Now a zero amount is treated like any other amount in the UPP hash, rather than being replaced by the uppAliasOnly literal string.

If the amount is zero, then the useAlias flag is automatically set with the assumption that a card alias is being requested. This should work with other payment type aliases too, such as the PayPal orderId.

We set useAlias to yes, as that appears most often in documentation. In some places it is specified as true, and other places 1. They all seem to work. For now.

[judgej]

Released as version 3.0.4

Not back-ported to 2.x. This can be done if there is a demand.