Britain's history and production updated

I've made some minor updates to Britain's history and vehicle production.

United States Production updated

Admiral Isoroku Yamamoto was right, the Japanese empire woke a sleeping giant when the Japanese attacked the United States in December 1941. The American, primarily locomotive and automobile, industry stepped up to the task and produced a phenomenal amount of weapons that supplied the Allied military fighting the Axis powers. Over 88,000 tanks alone were produced!
I've added a table that shows tank production by manufacturer.

Aircraft Production updated

I've added figures for all aircraft production in World War II by the main combatants.