Better error message when Atom.app is not found

atom.sh

@@ -3,6 +3,11 @@ ATOM_PATH=/Applications/Atom.app
 
 if [ ! -d $ATOM_PATH ]; then sleep 5; fi # Wait for Atom to reappear, Sparkle may be replacing it.
 
+if [ ! -d $ATOM_PATH ]; then 
+  echo "Atom Application not found at '$ATOM_PATH'" >&2
+  exit 1
+fi
+
 open -a $ATOM_PATH -n --args --executed-from="$(pwd)" --pid=$$ $@
 
 # Used to exit process when atom is used as $EDITOR