Allow users to skip all modules in header

workflow/qhtcp-workflow

@@ -354,8 +354,8 @@ print_header() {
 
   if [[ -z ${MODULES[*]} && -z ${EXCLUDE_MODULES[*]} ]]; then
     echo "Enter module #'s to run (by #, comma delimited)"
-    ((YES)) || read -r -p "Or hit Enter for default (ALL): " response
-    if [[ -n $response ]]; then
+    ((YES)) || read -r -p "Hit Enter for all (default) or '0' for none: " response
+    if [[ -n $response && $response -ne 0 ]]; then
       IFS=',' read -ra arr <<< "$response"
       for i in "${arr[@]}"; do
         MODULES+=("${ALL_MODULES[$((i-1))]}")