[test passed] Renamed: marker-icon@2x.png

Thanks to @lookfirst I installed the test suite and ran jake - everything passed just fine.  Updated the two files in the dist and now I'm committing them to the pull request.  If you want these changes in the mean-time pre-merge (assuming that the file name change is accepted), feel free to use: https://github.com/uberbuilder/Leaflet/tree/marker-icon-rename