CloudMade/Leaflet — pull request #623 by perliedman (2012-04-05 08:24:06+00:00)
Title: Ensure minimum and maximum zoom levels are updated when layers are added and/or removed

This fixes an issue where adding and removing layers (for example with the layers control) with different zoom level constraints, did not update _layersMinZoom and _layersMaxZoom to reflect the current set of layers, but rather to the "least common denominator" of all layers that had ever been added.