Audio improvements

[cmann1]

I'm not sure what's available to the engine but these would be useful if possible:

• Fix script audio. Is does not seem to be truly 2d - it behaves differently than built in sounds and does not pan left/right.
• min_distance and max_distance - Control over the distance at which the audio is full volume and completely faded out. Can do without min_distance if not possible.
• time - Get/set the current playback position.
• pan - Manual control over the left/right for non-positional sounds.
• pan_strength - A value between 0 and 1 for positional sounds. 0 = no panning, 1 = normal
• Allow volume greater than 1. If possible might want a separate method to avoid messing with existing scripts.