Pyalsaaudio

- Add DSD sample formats (contributed by lintweaker)
- Add Mixer.handleevents() to acknowledge events identified by select.poll (contributed by PaulSD)
- Add functions for listing cards and their names (contributed by chrisdiamand)
- Add a method for setting enums (contributed by chrisdiamand)

- fix 3 (we cannot get the revision from git for pip installs)

- document changes (this file)

- `PCM()` has new `device` and `cardindex` keyword arguments.

The keyword `device` allows to select virtual devices, `cardindex` can be
used to select hardware cards by index (as with `mixers()` and `Mixer()`).

The `card` keyword argument is still supported, but deprecated.

The reason for this change is that the `card` keyword argument guessed
a device name from the card name, but this only works sometimes, and breaks
opening virtual devices.

- new function `pcms()` to list available PCM devices.

- `mixers()` and `Mixer()` take an additional `device` keyword argument.
This allows to list or open virtual devices.

- The default behaviour of `Mixer()` without any arguments has changed.
Now Mixer() will try to open the `default` Mixer instead of the Mixer
that is associated with card 0.

- fix a memory leak under Python 3.x

- some more memory leaks in error conditions fixed.

- fixed several memory leaks (patch 3372909), contributed by Erik Kulyk)

- mostly reverted patch 2594366: alsapcm_setup did not do complete error
checking for good reasons; some ALSA functions in alsapcm_setup may fail without
rendering the device unusable