a list of scales or resolutions in the options to the constructor, from which
resolutions are calculated. Map now has a 'setScale' function which will allow
you to zoom to as close to a given scale as possible.
git-svn-id: http://svn.openlayers.org/trunk/openlayers@1171 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf