install ipython in user mode because 'sudo pip install ipython' fails on mac os x with the system python (#234)

requirements.txt

@@ -2,7 +2,6 @@ typing
 funcsigs
 subprocess32
 protobuf==3.0.0-alpha-2
-IPython
 boto3
 botocore
 Pillow

setup.sh

@@ -31,11 +31,13 @@ fi
 if [[ $platform == "linux" ]]; then
   sudo apt-get update
   sudo apt-get install -y git cmake build-essential autoconf curl libtool python-dev python-numpy python-pip libboost-all-dev unzip libjpeg8-dev graphviz
+  sudo pip install ipython
   sudo pip install -r requirements.txt
 elif [[ $platform == "macosx" ]]; then
   brew install git cmake automake autoconf libtool boost libjpeg graphviz
   sudo easy_install pip
   sudo pip install numpy
+  sudo pip install ipython --user
   sudo pip install -r requirements.txt --ignore-installed six
 fi
 pushd "$ROOT_DIR/thirdparty"