Added bool IsHelper(Func<DynamicNode,bool>), string IsHelper(Func<DynamicNode,bool>, string valueIfTrue), string IsHelper(Func<DynamicNode,bool>, string valueIfTrue, string valueIfFlase)
Added IsFirst/IsLast/IsOdd/IsEven helpers for checking position in current context/list
Added IsEqual for checking if the current node matches another by Id
Added IsDescendant/IsDescendantOrSelf/IsAncestor/IsAncestorOrSelf for checking relationships between two nodes