Add test files with different sample rate
Add test for interrupted playback when narrating audio with different sample rates
Fix interrupted playback with different sample rates
Add test files with mono and stereo audio
Add test for playback with different audio channels
Return correct number of read samples when decoding ogg audio with two channels
Fix double free crash when decoding mp3 audio with two channels

The decoded audio is not correct but understandable and narrator
does not crash.