miscellaneous  AI bug fixes & adjustments

git-svn-id: https://freeorion.svn.sourceforge.net/svnroot/freeorion/trunk@5672 dbd5520b-6a0a-0410-a553-f54834df5b05
Applied patch by qsswin to simplify stargate mechanics: Stargate activator and beacon buildings are gone, only a stargate building on each end and setting of the new "stargate send" and "stargate receive" foci is required.

git-svn-id: https://freeorion.svn.sourceforge.net/svnroot/freeorion/trunk@5673 dbd5520b-6a0a-0410-a553-f54834df5b05
new AI dependencies python file

git-svn-id: https://freeorion.svn.sourceforge.net/svnroot/freeorion/trunk@5674 dbd5520b-6a0a-0410-a553-f54834df5b05
Merge remote-tracking branch 'svn-mirror/master'