Queue of messages not working with !tts command.

[jadamrogers]

If I submit a message while another is playing, it doesn't play the message when the first is completed.

1. !tts 1111111
2. starts saying 111111
3. !tts 2222222 (submit while 111111 is playing
4. the 2222222 message never plays.

This only appears to be an issue when using the !tts command. If you have the option checked to play all messages it doesn't seem to be a problem.