Changelog

• Notify user when exiting focus on reaching max sessions.
• Add edit-config command for editing the config file.
• Add session_cmd config option and --session-cmd/-cmd CLI options for
  executing arbitrary commands after each session.
• Add ability to track and resume different timers.
• Display session tag in output.
• You can now launch a new instance of focus without quitting an existing
  instance as long as the countdown isn't actively running.
• Change focus stats --list to focus list.
• Change focus stats --delete to focus delete.
• Change focus stats --tag to focus edit-tag.
• Add ability to choose light or dark theme in config file.
• Support several additional time formats for stats filtering.