USSEP Changes Reverted and Tweaked 2.4 Backport

This mod reverts and/or tweaks over a thousand poorly implemented or arbitrary changes the USSEP makes. This includes properly fixing bugs, reverting erroneous or unnecessary changes, and restoring vanilla intent where a bug is not actually present. Exploits are not restored.

This is meant to serve as a vanilla-faithful mod but still keeps any appropriate bug fixes and also includes some extra relevant fixes not included in USSEP.

Backported for 1.5.97