Move APT dependencies and repos to their own files

apt-packages.txt

+python-software-properties
+pkg-config
+curl
+git
+python-virtualenv
+build-essential
+python-dev
+gfortran
+liblapack-dev
+libfreetype6-dev
+libpng12-dev
+libxml2-dev
+libxslt-dev
+yui-compressor
+graphviz
+graphviz-dev
+mysql-server
+libmysqlclient-dev
+libgeos-dev
+libreadline6
+libreadline6-dev
+mongodb
+nodejs
+npm
+coffeescript

apt-repos.txt

+ppa:chris-lea/node.js
+ppa:chris-lea/node.js-libs
+ppa:chris-lea/libjs-underscore

create-dev-env.sh

@@ -98,8 +98,9 @@ RUBY_VER="1.9.3"
 NUMPY_VER="1.6.2"
 SCIPY_VER="0.10.1"
 BREW_FILE="$BASE/mitx/brew-formulas.txt"
+APT_REPOS_FILE="$BASE/mitx/apt-repos.txt"
+APT_PKGS_FILE="$BASE/mitx/apt-packages.txt"
 LOG="/var/tmp/install-$(date +%Y%m%d-%H%M%S).log"
-APT_PKGS="pkg-config curl git python-virtualenv build-essential python-dev gfortran liblapack-dev libfreetype6-dev libpng12-dev libxml2-dev libxslt-dev yui-compressor nodejs npm graphviz graphviz-dev mysql-server libmysqlclient-dev libgeos-dev coffeescript libreadline6 libreadline6-dev mongodb"
 
 if [[ $EUID -eq 0 ]]; then
     error "This script should not be run using sudo or as the root user"
@@ -188,12 +189,15 @@ case `uname -s` in
             maya|lisa|natty|oneiric|precise|quantal)
                 output "Installing ubuntu requirements"
 
-                sudo apt-get install python-software-properties
-                sudo add-apt-repository ppa:chris-lea/node.js
+                # DEBIAN_FRONTEND=noninteractive is required for silent mysql-server installation
+                export DEBIAN_FRONTEND=noninteractive
+
+                # add repositories
+                cat $APT_REPOS_FILE | xargs -n 1 sudo add-apt-repository -y
                 sudo apt-get -y update
 
-                # DEBIAN_FRONTEND=noninteractive is required for silent mysql-server installation
-                sudo DEBIAN_FRONTEND=noninteractive apt-get -y install $APT_PKGS
+                # install packages listed in APT_PKGS_FILE
+                cat $APT_PKGS_FILE | xargs sudo apt-get -y install
 
                 clone_repos
                 ;;