USA
This fixes two major issues when playing as USA:
1) The Mexican American War. Having to take one state at a time takes an absurdly long and ahistorical time to complete. This mod changes the Manifest Destiny-Mexico completion event so Mexico hands over all US historical Western territory. To complete the Mexican portion of Manifest Destiny and initiate the territory transfer of all western states, the US must fully control Texas.
2) Oregon treaty with Great Britain. Currently expeditions are bugged. This eliminates the need for the West to be "mapped" via the expedition journal entries. Added an "Oregon Treaty" decision as the events were being flaky. Events are still there and seem to work sometimes, but the decision is there for a backup. AI should take the decision.
