v0.3

• Modd no longer exits when there are script errors on first run. Instead,
  blocks with errors will be progressively started when there are applicable
  changes.
• +onchange option to prep commands tells modd skip execution on startup, and
  run only when there's a detected change. (thanks Thomas B Homburg
  thomas@homburg.dk)
• @shell magic variable to switch the shell used to execute commands. Current
  options are "bash" and "exec". (thanks Daniel Theophanes
  kardianos@gmail.com)
• Modd now uses an exponential backoff strategy for daemon restarts (Josh
  Bleecher Snyder josharian@gmail.com)
• Bugfix: Fix a format string issue that could cause some program output on the
  console to be corrupted. (thanks Yoav Alon yoava333@gmail.com)