Notifications shouldn't interrupt speech

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Launch TalkBack.
2. Receive an incoming notification while text is speaking.

What is the expected output? What do you see instead?

Expected: Speech should not be interrupted to speak notifications. I'd rather 
hear the entire notification spoken, or hear whatever is currently being read 
followed by the notification.

Actual results: Notifications cut off speech. This is especially problematic 
when the notification cuts off another notification. So if I'm in a chat then 
receive an email, the email notification cuts off the chat message and makes 
participating in the chat difficult.

What version of the product are you using? On what operating system?

Android 4.4.4, TalkBack 4.2.0B1

Please provide any additional information below.

Original issue reported on code.google.com by [email protected] on 1 May 2015 at 3:27