Some updates

Hello.

First, my appologies for the low frequency of updates. The last two weeks have been more busy than normal.

The second campaign is ready. The third one is currently 76% done. These maps are taking longer to fully test and balance, as they are supposed to be hard.

Some A.I. improvements are made specifically to give differentiated gameplay for some missions.

For example:

• An important allied unit may not risk itself too much and stay near the base/retreat to repair more often;
• Some enemy units guard a specific area, never getting out of their hiding.

Some secondary progresses includes:

• Replacement of old placeholder sounds;
• Cleaned some unused sprites;
• Minor unit rebalancing based on their performance during the campaign testing.