Migrating formulae: glfw2 and glfw3

Per Homebrew [PR #22410](https://github.com/mxcl/homebrew/pull/22410#issuecomment-24097791):

glfw2: from Homebrew/homebrew/glfw @ [4392eba](https://github.com/lloeki/homebrew/blob/4392eba/Library/Formula/glfw.rb)
glfw3: from lloeki/homebrew/glfw3 @ [40198dc](https://github.com/lloeki/homebrew/blob/40198dc53ddb1a887a5f7ddc9b71f4c7a21253fc/Library/Formula/glfw3.rb)