Thoughts after reading the help screen

[JoshCheek]

Reread it and update it. Examples could also be a bit more comprehensive, they seem a bit too minimal.

• Flag --local-cwd should probably be named --file-cwd
• For --stream, link to a list of events
• Should probably emit an event for Dir.pwd, as well.
• Should probably list deprecated flags and suggest what to use in their place.
• Should probably allow - for filename to mean stdin (it's redundant, but more consistent with other programs)
• Should probably allow -- to tell SiB to quit reading args and set them as the program's ARGV
• For --local-cwd, this example would probably be better:

  echo __FILE__ | seeing_is_believing
  echo __FILE__ | seeing_is_believing --local-cwd
  

• For -I and -r, specify how they deal with relative paths