BTS 3.19 Patch

Firaxis surprised the community yesterday with patch 3.19 for BTS. The discussion is already well underway, but the general consensus seems to be favorable.

Most of the changes are pulled from the Unofficial Patch and Better AI. It also includes the multiplayer cargo unloading OOS fix. The only verified bug so far is in an adjustment to the overflow gold; it's all but completely eliminated.

While there are a few minor Python changes we need to add, BUG 3.5+ is completely compatible with 3.19 as-is. The missing Python fixes are remnants of 3.17's No Espionage option and only visual in nature.