[feature] Multiple Pomo instances at the same time

[arpanetus]

Wouldn't it be nice to be able to use multiple pomo instances at the same time, if you've paused doing another task and started doing some other?

[kevinschoon]

The simplest solution would be to enable a flag such as --socket to avoid the conflict. Alternatively it could check for an existing socket and if it exists prefix the path with an incrementing number e.g. ~/.pomo/pomo-1.sock.

I'll plan to implement this in the coming release or feel free to create a PR.

Thanks for the suggestion @arpanetus!