Version 0.1.3 - add a proper fork manager with quick installation times

• Make flags/arguments more robust. Optional non-positional arguments are now supported, as long as they are the last arguments.
• emu fork switch and emu fork list commands added. Uses one singular git repo and adds remotes of forks so that the time to install a new fork is reduced significantly since git is able to re-use blobs.
  • A one-time setup is required when using the fork command, this full clones commaai/openpilot which may take a bit of time on first use.
  • Change remote of origin to commaai so that no additional logic is required. Aliases of stock openpilot are: ['stock', 'commaai', 'origin']
  • Stores all installed forks and forks' branches in /data/community/forks/forks.json so that the forks command can easily identify when it needs to track and create a branch or just check it out.
  • You should still run git pull to make sure you get the latest updates from the fork you're currently switched to.
• Dynamic loading of commands. If a command has an exception loading, it won't crash the CLI. Instead you will see an error when you try to call emu