Added ability to set MediaPlayer.OnErrorListener in prepare() and prepareAsync()

[oleynikd]

Now you can set OnErrorListener in prepare() and prepareAsync() methods:

mVideoView.prepareAsync(new MediaPlayer.OnPreparedListener() {
    @Override
    public void onPrepared(MediaPlayer mp) {
        Log.v("mVideoView", "onPrepared");
    }
}, new MediaPlayer.OnErrorListener() {
    @Override
    public boolean onError(MediaPlayer mp, int what, int extra) {
        Log.e("mVideoView", "Error: " + waht);
        return false;
    }
});

Basically added 2 new methods:

public void prepare(@Nullable MediaPlayer.OnPreparedListener listener, @Nullable MediaPlayer.OnErrorListener eListener)
            throws IOException, IllegalStateException

public void prepareAsync(@Nullable MediaPlayer.OnPreparedListener listener, @Nullable MediaPlayer.OnErrorListener eListener)
            throws IllegalStateException

[yqritc]

@oleynikd Thanks for PR. I'm welcome to add an ability to set error listener, but I prefer to define it as separate method like the following.

public void setOnErrorListener(@Nullable MediaPlayer.OnErrorListener listener) {
    mMediaPlayer.setOnErrorListener(listener);
}

Please tell me if u have any trouble with this.

[yqritc]

I just published ver 1.0.2, which has setOnErrorListener.