Install command to do static analysis on bash scripts

src/freedombone-image-customise

     chroot "$rootdir" apt-get -yq dist-upgrade
     chroot "$rootdir" apt-get -yq install ca-certificates
     chroot "$rootdir" apt-get -yq install apt-utils
+    chroot "$rootdir" apt-get -yq install shellcheck
 
     if [[ $ARCHITECTURE == 'amd64' ]]; then
         chroot "$rootdir" apt-get -yq install linux-image-amd64

src/freedombone-utils-setup

     fi
 }
 
+function install_shellcheck {
+    # Used by the tests command
+    apt-get -yq install shellcheck
+}
+
 function setup_utils {
     read_config_param "PROJECT_REPO"
     write_config_param "PROJECT_REPO" "$PROJECT_REPO"
 
     function_check setup_powerline
     setup_powerline
+
+    function_check install_shellcheck
+    install_shellcheck
 }
 
 function setup_email {