Yeah, that doesn't exist any more and we have to configure compiz manually from what I know. May be they removed it because of problems that may arise with configuring unity that way, I am not sure why.
Since you are on 12.04 or later, and I am assuming that you have compiz installed, if not use
sudo apt-get install compizconfig-settings-manager
to install it.
NOTE:
From there on you can configure it in different ways as you like. Here are more places where you can read some material/guides on cool tweaks you can do with this tool once you install it.
http://www.howtogeek.com/101006/how-to-tweak-unity-on-ubuntu-with-the-compizconfig-settings-manager/
http://www.makeuseof.com/tag/change-settings-ubuntu-unity-compizconfig-settings-manager/
How to change color of unity workspace border, and window resize
If you find some feature name not understandable, take a look at compiz wiki and read what that feature does, and then tweak it if you want to. Happy tweaking!