add a helper function for taglist string
add a helper function for taglist string

git-svn-id: aefc35c4d2a558cdb840b19a7b656ddc5705d5d4@32 878ac3a0-d211-204e-1a3b-ba5334b63f43

jeffkowalski/evernote-mode,rubbish/evernote-mode,pymander/evernote-mode