… where declaration for json schema attribute were redundant.

update 'N/A' to 'none' in moduletool properpty. Add 'description' keyword as a definition since its used in multiple location in JSON file.
update example configuration files and main config.yml to use 'none' instead of 'N/A' for moduletool
remove reference to compiler_builder used for printing builders via compiler schema.
Add example buildspec for compiler exclude using keyword 'exclude'