The 'contains' helper accepts objects and some other new functionality

[villesiltala]

Add a functionality for the contains helper to check if an object has a specific key and/or a value.

If an object is passed as the haystack, then the helper loops through all the keys and does a loose comparison on the values by the given needle and returns true if the needle is found. The key paramater will be changed to map.

{@contains map=haystack value="needle" /}

If only the key parameter is set, then the helper checks whether the given key is set in the array/object.

{@contains map=haystack key="needle" /}

If the key and value parameters are set, then the helper checks whether the given key is set in the array/object and it loosely matches the given value.

{@contains map=haystack key="needle" value="matching_value" /}