Fixed a bug where the orderings were not saved in the query
Added support to specify an associative array as constraint

Example:

	$query->setConstraint(array(
		'price' => array(
			'value' => 0.0,
			'operator' => \Cundd\Rest\VirtualObject\Persistence\QueryInterface::OPERATOR_GREATER_THAN,
		)
	));
Added tests for the enhanced queries
Added the expiresHeaderLifeTime TypoScript variable to send an expiration header for cached responses
Removed the cacheLifeTime from ext_typoscript_setup.txt (fixing issue #2)
Merge branch 'feature/virtual-object-query-operator' into develop