Update bots to use chatter 0.3. Closes #131.

[cowboy]

• Update chatter to ~0.3.0 in package.json.
• Restart bot when .env file changes.
• Move bot helper methods into reusable lib/bot-helpers module.
• Update newbot to use chatter 0.3.
  • Add Robocoup icon.
  • Minor cleanup.
• Update thanksbot
  • Add thanksbot icon.
• Update pombot to use chatter 0.3.
  • Add tomato icon.
  • Enable logging of stack traces on exceptions.
  • Add "getCommand" command name formatting helper function.
  • Convert sub-command factories into commands.
  • Use createArgsAdjuster to pass pom instance and name formatting helper function into commands instead of using factories and closures.
  • Reduce repetition in SlackBot createMessageHandler code.
  • Use heredoc-tag lib to format a few lines that would have been > 120 chars.