v4.0.0-alpha.9

Overhauls the TUI in order to provide a full UI for console users. This includes:

• Refactor for TUI as class. Fix #42.
• Add a Curses console and waiting screen.
• Add PythonDialog as alternative to Curses
  • Check if user has an up-to-date dialog package.
  • Replicates Curses functionality, except Menu + Console
  • Adds a file picker
  • Adds a package install screen
• Implement threading for TUI
• Add download_packages(). Rework code for individual package testing.
  • Add pythondialog.buildlist
  • Add pythondialog.checklist
• Fix #104
• Various code fixes

It also includes some fixes for #106 and prep work for #22.

Also fixes #76, #104, #111, #115.