Use the .ini formatted index files now (created/migrated by update.js.

New per-file properties supported:
- ars: access requirement string
- tail: print (view) the last n-lines of a text file rather than entire file
- mode: override P_mode flags (default is now P_OPENCLOSE | P_CPM_EOF)

The 'E' opertor command allows each file description to be edited too.