Add support for reading config entries from Jump.Location.dll.config, minor cleanup

This is related to jumpstat -scan addition. I added a config entry named "Jump.Location.Scan.MaxSubFolders" to App.Config but the the code didn't see that because DLLs don't have their own config file. My work around is based on this article: http://stackoverflow.com/questions/17960/powershell-app-config
Please, use WriteWarning() instead or Console.WriteLine().
In other output in the same file, please use WriteWarning, WriteVerbose, WriteProgress, etc