don't fill bitmapdata in imagepicker - safer to load file from path

Previously we removed the call to drawPickedImageToBitmapData on Android because it was sometimes slow enough to hang the app dangerously long, and just loading the file from the path in AS3 worked better anyway. This change makes the behavior the same between Android and iOS, and also removes some unused code that calls copyPickedImageJPEGRepresentationToByteArray, which is also expensive.