We call sysctl to determine which exact Mac model we are running on and optimize as well as possible.
CONSTANTS are the far saner choice for these important parameters. Split env up so I can redefine the CONSTANTS in unittest.rb.
Moved Forumla and Cellar/homebrew into Library. This way the homebrew core files are more sensibly placed, Cellar is more internally consistent and only generated. And Homebrew is ready for use straight out of the tarball.
