- Removed 'usage' and 'help' commands. They won't be of much use once the
  prompt interface goes out the window. Usage has already been purged from
  the workload profiles

- Purged some redundant rules from grammar

- Tightened the rules for 'define file' and 'define fileset'. The attributes
  are different between the two (fileset attributes are a superset of file
  attributes), and any attempt to defy that is ignored by the code, so it
  should throw a syntactic error