Added wavio.read() as fallback for cases where scipy.wavfile cannot r…

[ganileni]

…ead a wave file.

scipy.wavfile cannot read 24-bit files and is in general prone to failure.
If it fails reading, let's fall back on wavio, a library that works most of the times.
wavio is just a wrapper around Python's wave standard library.

[justinsalamon]

Thanks for the contribution. However, I believe that if we want to add an audio reading dependency, it should be soundfile, which is more mature and supports a wide variety of audio formats. Would you be interested in updating this PR to use soundfile instead?

p.s- it's always best to start by posting an issue before posting a PR so we can discuss prior to implementation. Thanks!