Fixing up issues in install guide

docs/get_started/install.md

@@ -73,6 +73,7 @@ The following installation instructions have been tested on Ubuntu 14.04 and 16.
 **Step 1**  Install virtualenv for Ubuntu.
 
 ```bash
+$ sudo apt-get update
 $ sudo apt-get install -y python-dev python-virtualenv
 ```
 
@@ -125,7 +126,7 @@ Installing *MXNet* with pip requires a latest version of `pip`. Install the late
 
 ```bash
 $ sudo apt-get update
-$ sudo apt-get install -y wget python
+$ sudo apt-get install -y wget python gcc
 $ wget https://bootstrap.pypa.io/get-pip.py && sudo python get-pip.py
 ```
 

setup-utils/install-mxnet-osx-python.sh

@@ -66,13 +66,14 @@ download_mxnet() {
 		mv ${MXNET_HOME} ${MXNET_HOME_OLD}
 	fi
 	echo "Downloading MXNET source repositories from github"
-	git clone https://github.com/dmlc/mxnet.git ${MXNET_HOME} --recursive 
+	git clone https://github.com/dmlc/mxnet.git ${MXNET_HOME} --recursive
 }
 
 download_mxnet
 runme brew update
 runme brew_pkg_install pkg-config
 runme brew_pkg_install python
+runme pip install --upgrade pip
 brew install homebrew/science/openblas
 runme brew_pkg_install opencv
 # Needed for /usr/local/lib/graphviz to be created