Bump version
Return more specific "tiny download" error class

This will allow catching from services, if needed.
Workaround for bad Yandex downloads

This attempts to workaround the bad Yandex downloads by retrying the
download (under very specific circumstances involving the tiny files).
Release of v1.2.3

Works around a Yandex server problem where Yandex will occasionally
return a tiny MP3 instead of the actual playback.

(Merge branch 'pre/v1.2.3' into stable)