Heuristic for error activity about hyper

[hharnisc]

To me it makes sense to make the tab text red if the last exit code was non-zero. Digging through the code to see how it could be done.

[hharnisc]

Seems tricky! Taking a look at the child_pty source code it looks like there might be a way https://github.com/Gottox/child_pty/blob/master/lib/child_pty.js#L86 but it could also be referring the exit code of the command ran with spawn (in this case defaultShell).

Another option might be to change the tab to red of there's activity on stderr, but it looks like the event doesn't get triggered by child_pty https://github.com/Gottox/child_pty/blob/master/lib/child_pty.js#L100