Fix #801 by changing setup script

ubuntu_setup.sh

@@ -1,16 +1,25 @@
 apt-get update
 apt-get install -y apache2
+
 curl -sL https://deb.nodesource.com/setup_10.x | sudo -E bash -
+
+# Add yarn PPA
 curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -
 echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list
 apt-get update
 apt-get install -y nodejs
 apt-get install -y python-pip
 pip install pipenv
 
+# Uninstall cmdtest (if present) to install the correct yarn.
+apt-get remove cmdtest
 apt-get install -y yarn
 yarn add global parcel-bundler
 sysctl fs.inotify.max_user_watches=99999
 export PATH="$(yarn global bin):$PATH"
 
 pipenv install && pipenv shell
+
+# Perform cleanup
+apt-get autoremove
+apt-get clean