Capture editor launch error and display URL to access

[theganyo]

There have been some unexplained issues with Windows 8 opening the browser to the editor URL. See: http://community.apigee.com/questions/876/swagger-not-opened-on-issuing-edit-command.html#comment-1976

It would be useful to allow the user to launch their browser to the link manually when a127 cannot. We should capture the error and display a message with the URL for the user.