lookatme v3.0!

There's a decent amount of work that has queued up for lookatme, including many bug fixes and new features.

Some of the biggest features that I want to include in the v3.0 release of lookatme are:

• Progressive slide rendering
  • already has a PR, just needs to match the new refactoring
• Basic HTML support! (Yay for nested lists in tables, fg/bg color, etc.)
  • already in place, needs more testing
• Table column sorting
  • almost there!
• Native image rendering (if the terminal supports it)
  • TODO

Along with this, we should also include fixing all remaining bugs. None of them are major and should be able to be knocked out in short order.