SphericalMercator changes. Note that this explicitly does *not* include
r4182 , so as to keep changes to a single logical set: that should be
filed in a seperate bug if it can be reproduced against trunk after this
commit. Hooray for Tim, thanks for all the feedback, onward and upward!
(Closes#686)
git-svn-id: http://svn.openlayers.org/trunk/openlayers@4221 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf
