fixed a bug in ROS installation, updated README

Sourcing .bashrc from install_ros.sh didn't have any effect, since
.bashrc needs to be sourced from an interactive shell. Because of this,
it was required to restart the terminal for ROS to work. Now, the ROS
startup scripts are sourced directly from the installation script,
thus eliminating the need to restart the terminal.

Added instructions to README to check the installation success.

setup/install_ros.sh

@@ -24,8 +24,8 @@ sudo rosdep init
 rosdep update
 
 echo "Environment setup"
+source /opt/ros/indigo/setup.bash
 echo "source /opt/ros/indigo/setup.bash" >>${HOME}/.bashrc
-source ${HOME}/.bashrc
 
 echo "Get rosinstall"
 sudo apt install python-rosinstall -y