reduced range of AI aggression distribution to be 75% max aggression and 25% one level lower

git-svn-id: https://freeorion.svn.sourceforge.net/svnroot/freeorion/trunk@5757 dbd5520b-6a0a-0410-a553-f54834df5b05
AI fix to eliminate (or at least reduce) AI streaming fleets into known death

git-svn-id: https://freeorion.svn.sourceforge.net/svnroot/freeorion/trunk@5758 dbd5520b-6a0a-0410-a553-f54834df5b05
Merge remote-tracking branch 'svn-mirror/master'