Just malloc all of the audioOutput array in one shot
to avoid fragmentation and to improve cache locality
when iterating through the array.

We also know name and type members of the AudioOutput
struct won't change in the config, so there's no
need to strdup them.

newAudioOutput => initAudioOutput

git-svn-id: https://svn.musicpd.org/mpd/trunk@4515 09075e82-0dd4-0310-85a5-a0d7c8717e4f