#2 AI improvements

[Steve Hawkins]

Here's a patch for the ai that simplifies most of the logic in the ai classes except for AIHard - which has expanded logic for deeper, yet quick, planning.

A hard player will attempt to be more balanced with attack/defense using its relative standing in the game as a guide. It also has a greater emphasis on capturing continents rather than just harassment.

Most of the logic is still stateless and could be refined much further. The capital/mission logic is also a little weak as it is mostly just an extension of the hard logic with specific weighting adjustments, rather than more in-depth logic. I also kept the logic somewhat in line with the rest of the project which seems mostly written for 1.4, but could easily be updated if requested.

Let me know if you have any questions and if this is of interest.

[Steve Hawkins]

here's a refinement that also has better capital play.

[Yura]

these changes are included as of v1.1.1.3