Revision 614

genisoimage.1 cleanup.  Step 2: vertical whitespace.
Blank lines are technically not allowed in nroff source.

- Visually separate new sections (.SH) with a comment line
  .\" ----------------------------------------
  instead of whitespace.

- Implement indented example lines using .IP (new indented paragraph)
  where possible - if the context is already indented, use .sp and
  manual indentation, for now.  Might fix this later using double
  indentation, but I don't know how to specify that, offhand.

Also use .IP to begin new paragraphs in indented sections (option
descriptions) rather than .sp.