Preload and ns play

* Make sure that the preload boolean gets set correctly based on the value specificed in html5 (unless preload=='none', set preload to true).
* If we are preloading, we want to initialize the netconnection and netstream but *not* play. So, immediately after the ns is initialized and called `play` to add in the video url, we pause the ns.
* We are are autoplaying, or play has been called, resume the ns.
Just checked it out and no error is thrown. If preload attribute isn't set on the video element, `loaderInfo.parameters.preload` is set to `undefined`, but no error is thrown and we preload the video.