Cannot hash AudioSound in master

In current master branch, there is a regression in Audio3DManager.py, because AudioSound is no longer hashable:

Traceback (most recent call last):
  File "/usr/share/panda3d/direct/showbase/Audio3DManager.py", line 266, in update
    vel = self.getSoundVelocity(sound)
  File "/usr/share/panda3d/direct/showbase/Audio3DManager.py", line 142, in getSoundVelocity
    if (sound in self.vel_dict):
TypeError: unhashable type: 'panda3d.core.AudioSound'
:task(error): Exception occurred in PythonTask Audio3DManager-updateTask

I fixed this by using id(sound) as keys, but I’m not sure if that is the correct fix. Was AudioSound intended to become unhashable?

Someone else just reported this an hour ago on IRC, and I’m working on a fix.

FYI id(sound) is unreliable for Panda types since multiple Python objects may be created to represent one Panda object. Use sound.this to get the underlying C++ pointer instead - this is what hash(sound) would return if it were working.

Fixed. Sorry for the inconvenience.

Thanks!