Remove the old "InactivePanes_" workaround
Safety net for accidentally deleting all packages
Make debugging disableable
Do small restructuring and give appropriate names
ST2: Fix new and unnamed tabs not dimmed at all

Also attempt to improve loading new projects, not sure if this will
actually help with anything.
Some misc changes (comments, docstrings)
Attempt to fix crashes when dragging tabs

This only occurs in multi-group layouts and doesn't seem to follow a
pattern, or at least I couldn't find one. Adding a timeout (only for
ST2) seems to make that go away. With the way we dim schemes now this
shouldn't create flittering either.

The next release will probably be the last for ST2.
Revise README.md