Older/Alternative version checks could be removed.

[DannyvdSluijs]

During work on the project I've found some version checks for older/alternative versions. These can be removed.

json-schema/tests/ValidatorTest.php

Lines 34 to 39 in d862d4c

	if (version_compare(phpversion(), '5.5.0', '<')) {
	$this->markTestSkipped('PHP versions < 5.5.0 trigger an error on json_encode issues');
	}
	if (defined('HHVM_VERSION')) {
	$this->markTestSkipped('HHVM has no problem with encoding resources');
	}