Update README for Homebrew.

glfw3 is in the `homebrew/homebrew-versions` repository.

README.md

@@ -9,14 +9,10 @@ Servo welcomes contribution from everyone.  See
 
 ## Prerequisites
 
-Note, on systems without glfw3 packages, you can compile from source. An
-example can be found in [the TravisCI install
-script](etc/ci/travis.install.sh).
-
 On OS X (homebrew):
 
 ``` sh
-brew install automake pkg-config python glfw3 cmake
+brew install automake pkg-config python cmake
 pip install virtualenv
 ```
 
@@ -32,7 +28,7 @@ On Debian-based Linuxes:
 sudo apt-get install curl freeglut3-dev \
     libfreetype6-dev libgl1-mesa-dri libglib2.0-dev xorg-dev \
     msttcorefonts gperf g++ cmake python-virtualenv \
-    libssl-dev libglfw-dev libbz2-dev
+    libssl-dev
 ```
 
 On Fedora:
@@ -41,7 +37,7 @@ On Fedora:
 sudo yum install curl freeglut-devel libtool gcc-c++ libXi-devel \
     freetype-devel mesa-libGL-devel glib2-devel libX11-devel libXrandr-devel gperf \
     fontconfig-devel cabextract ttmkfdir python python-virtualenv expat-devel \
-    rpm-build openssl-devel glfw-devel cmake bzip2
+    rpm-build openssl-devel cmake
 pushd .
 cd /tmp
 wget http://corefonts.sourceforge.net/msttcorefonts-2.5-1.spec
@@ -53,7 +49,7 @@ popd
 On Arch Linux:
 
 ``` sh
-sudo pacman -S base-devel git python2 python2-virtualenv mesa glfw ttf-font cmake bzip2
+sudo pacman -S base-devel git python2 python2-virtualenv mesa ttf-font cmake
 ```
 
 Cross-compilation for Android: