Added the use of a gem called rgen_ext which is an extension of rgen and...

Added the use of a gem called rgen_ext which is an extension of rgen and makes traversing our ruby model more flexible, requiring less knowledge of the specific child nodes. It does not affect our current implentation, but will give us more power while generating code in the future. I also moved the ruby model code into its own ruby file called server_model.rb which can be used to more easily define relationships, especially if the XML itself changes. The only extra requirment is the install of the rgen_ext gem.