Robot name 20141001 rc

Changes made:
-clean up name assignment
-move error call
-refactor generate_new_name
-remove generate_char and generate_num methods
You should try to limit the use of @variables (instance) to initialization functions. (Practical Object Oriented Design In Ruby by Sandy Metz), and creating attr_reader/writer/accessors as needed; this reduces the likelihood you will set variables elsewhere in your code that may break functionality of your classes, or having to hunt down every place it's set.