revset: added ascending and descending methods to _addset This methods are intended to duck-type baseset, so we will still have _addset as a private class but will be able return it without wrapping it into an orderedlazyset or a lazyset.

revset: added filter method to _addset This method is intended to duck-type baseset, so we will still have _addset as a private class but we will be able return it without wrapping it into an orderedlazyset or a lazyset.

revset: added comments to all methods needed to duck-type from baseset All this methods are required to duck-type for any class that works as a smart set.

revset: use more explicit argument names for baseset methods Use other instead of x and condition instead of l