[WIP?] Let ArrayHelper::getColumn behave like array_column

This should ArrayHelper::getColumn behave as the PHP 5.5 function array_column.

However, I'm not sure if php default behaviour should be kept or changed (as we have additional functionality).
Nativly, if second parameter is null and thrid is not set, the entire array is returned. This pr returns false instead.

http://php.net/manual/en/function.array-column.php