Fix token auth

[Nekroze]

Hello,

In using this library we have found issues with the FatZebra->token_authorization method attempting to use several variables that do not exist.

This PR consists of 3 commits, the first adds some docker-compose.yml files for the test and example directories to more easily run tests locally with different PHP versions.

The next commit implements a test that if run will fail on:

PHPUnit 6.5.13 by Sebastian Bergmann, Julien Breux (Docker) and contributors.

...............IE                                                 17 / 17 (100%)

Time: 13.29 seconds, Memory: 4.00MB

There was 1 error:

1) GatewayTest::test_token_authorization
Undefined variable: token

/app/FatZebra.class.php:238
/app/test/gateway_tests.php:253

ERRORS!
Tests: 17, Assertions: 39, Errors: 1, Incomplete: 1.

The final commit passes the previously added test by fixing the test_authorization method.

[Nekroze]

Should this PR also bump the semver PATCH level?

[Nekroze]

Should this PR also bump the semver PATCH level?

Added 4th commit to do this, once merged the top commit should be git tagged 1.2.2

[Nekroze]

I have also had to patch the customer_ip logic as it made too many assumptions about the environment making it harder to run in various test/staging environments.