Pyalsaaudio

- Fix alsamixer_getvolume (112 from stephensp)

- Support decibel, percentage, and raw volumes in getvolume, setvolume, and getrange (109 from chrisdiamand)

- Added keyword arguments for channels, format, rate and periodsize
- Deprecated `setchannel`, `setformat`, `setrate` and `setperiodsize`

- Added four methods to the `PCM` class to allow users to get detailed information about the device:

- `getformats()` returns a dictionary of name / value pairs, one for each of the card's
supported formats - e.g. `{"U8": 1, "S16_LE": 2}`,
- `getchannels()` returns a list of the supported channel numbers, e.g. `[1, 2]`,
- `getrates()` returns supported sample rates for the device, e.g. `[48000]`,
- `getratebounds()` returns the device's official minimum and maximum supported
sample rates as a tuple, e.g. `(4000, 48000)`.

(82 contributed by jdstmporter)

- Prevent hang on close after capturing audio (80 contributed by daym)

- Return an empty string/bytestring when `read()` detects an
overrun. Previously the returned data was undefined (contributed by jcea)

- Unlimited setperiod buffer size when reading frames (contributed by jcea)

- Fix Python3 API usage broken in 0.8.3