Implement extensible AI

[dom111]

Build on the Strategy, Routine etc classes to have all functionality opt in by exposing relevant Strategys to handle special Units or features.

This will be a selection of base- modules that are likely to be included in the civ1- modules for the area. Examples:

• Diplomats (when to produce, how to use etc)
• Caravans and trade routes
• Exploration (which areas to prioritise)
• Managing trade rates
• Automating Workers to "improve" the areas
• Good sites for Citys

and everything else!