Allow mutual allies to garrison in each others buildings. Patch by mimo. Fixes #1807.

git-svn-id: http://svn.wildfiregames.com/public/ps/trunk@13357 3db68df2-c116-0410-a063-a993310a9797
Fix tests. Refs #1807.

git-svn-id: http://svn.wildfiregames.com/public/ps/trunk@13358 3db68df2-c116-0410-a063-a993310a9797
Merge remote-tracking branch 'remotes/trunk'