Add 700D Audio Stubs and meter and beep features

Created originally on Bitbucket by mk11174 (Mathew Kelly)

Was already merged in Bitbucket before import, marked as merged by the import user

Source changeset not longer availableat the time of import. Commit listwill look empty

This will get mlv_snd working with mlv_rec plus get beep going and also meters while recording movie or mlv_rec