For jplayer, the preload attribute is output wrong

Problem/Motivation

Steps to reproduce

Use jplayer as the audio player. Look at the `` tag that is output. It will have preload=true or preload=false depending on the lazyload setting, but neither of those is a valid value for preload.

Proposed resolution

In js/jplayer.builder.js, do something like this instead:
`preload: settings.lazyload ? "none" : "auto",`

Remaining tasks

User interface changes

API changes

Data model changes