app.config

http://www.codeproject.com/Articles/16466/Unraveling-the-Mysteries-of-NET-Configuration#elementcolls

http://msdn.microsoft.com/en-us/library/2tw134k3.aspx

http://www.codeproject.com/Articles/32490/Custom-Configuration-Sections-for-Lazy-Coders

http://msdn.microsoft.com/en-us/library/2tw134k3.aspx