Follow all the instructions to install the base version of ROS: Install ROS-Base. Please make sure you have followed all the ROS installation steps, including calls to rosdep.
sudo apt-get install python-wstool
Now follow the steps for your particular ROS version.
Assuming you are in the moveit folder created above,
You will have to do this every time you work with this particular source install of the code. Assuming you are in the moveit folder created above,
source devel/setup.bash # or .zsh, depending on your shell