Remove interpreter specification

These script fragments should only ever be sourced rather then directly
executed

script/include/helper_functions.inc.sh

@@ -1,10 +1,9 @@
-#!/bin/bash
-
 # helper_functions.inc.sh: General helper functions
 
 # Check pip to see if the given package is installed
 # (returns 0 if installed, 2 if not installed)
 check_pip_for () {
+  # Use 'pip list' to see if the requested package is already installed
   return $(pip list --format=columns --disable-pip-version-check | \
 	  grep -Fe "${1}" >/dev/null 2>&1)
 }