Tech Tree Update.

Rewrote menus so they are more dynamic.
Added TechTree command argument.
Added NavigationHandler to help track country and tank types when
navigating the item menus.
Updated TODO list.
Added the ability to unlock any tank if the player has enough money and
experience.
Players now start with Tier 1 tanks.
Added missing information to the Japanese enum.
Added money and experience values to tanks.