Minor changes, typo and WMS URL, to get example working

Two minor changes:

- removed comma after last member in mapoptions.params object
- changed WMS URL to "http://add.antarctica.ac.uk/geoserver/wms?" (the original did not respond)
Merge pull request #20 from justb4/master

Minor changes, typo and WMS URL, to get example working
Merge remote-tracking branch 'upstream/master'