Merge pull request #148 from tomhoover/patch-1

commit c507bdd broke zsh -- this fixes it

z.sh

@@ -44,7 +44,7 @@ _z() {
         # don't track excluded directory trees
         local exclude
         for exclude in "${_Z_EXCLUDE_DIRS[@]}"; do
-            case "$*" in $exclude*) return;; esac
+            case "$*" in "$exclude*") return;; esac
         done
 
         # maintain the data file