Adjusting reasearch boosters to aproximately reasonable levels.  Not playtested.  Descriptions should all be accurate.

git-svn-id: https://freeorion.svn.sourceforge.net/svnroot/freeorion/trunk@5698 dbd5520b-6a0a-0410-a553-f54834df5b05
fixed depeleted ruins giving no tech boost, and halved distributed thought's research bonus.

git-svn-id: https://freeorion.svn.sourceforge.net/svnroot/freeorion/trunk@5699 dbd5520b-6a0a-0410-a553-f54834df5b05
Merge remote-tracking branch 'svn-mirror/master'