Cleaned up documentation in some files. Auto-generated documentation is nicer now.
Created errors.go file. Converts some YAML errors into RAML errors with better context. Still requires a lot of work.
Added test for failed parsing of a bad RAML file.
Fixed badly unmarshaled types (namedParameter, Body).
Added "format" documentation field to NamedParameter, will consider using in outputting better errors (--verbose style?)