AI mods to try keeping up with the Jonses.

git-svn-id: https://freeorion.svn.sourceforge.net/svnroot/freeorion/trunk@5751 dbd5520b-6a0a-0410-a553-f54834df5b05
fixed Gaia building so can't attempt to build if gaia special already present

git-svn-id: https://freeorion.svn.sourceforge.net/svnroot/freeorion/trunk@5752 dbd5520b-6a0a-0410-a553-f54834df5b05
Merge remote-tracking branch 'svn-mirror/master'