Add tests for alternate Cache Drivers

[drbyte]

Currently the test suite only tests the default in-memory array cache.

I sometimes manually run the test suite against alternate Cache Stores:

laravel-permission/tests/TestCase.php

Lines 115 to 118 in ec9079a

	// FOR MANUAL TESTING OF ALTERNATE CACHE STORES:
	// $app['config']->set('cache.default', 'array');
	//Laravel supports: array, database, file
	//requires extensions: apc, memcached, redis, dynamodb, octane

It would be ideal to automate this.