Change Homebrew curl url, added some npm globals

Homebrew no longer lives at [/mxcl/homebrew](https://github.com/mxcl/homebrew), it now lives at [/Homebrew/homebrew](https://github.com/Homebrew/homebrew). `curl` should handle this with `-L`, but on a fresh install of Mavericks `curl -fsSL https://raw.github.com/mxcl/homebrew/go/install` was returning `400: Bad request` for me, so probably worth changing just incase.

Also added some useful npm global packages that I had to install in my first week, including pliers.