tissue does not clean up Unix socket when deployed with shepherd

When deployed with shepherd, and stopped using something like herd stop tissue, the tissue web server does not clean up its Unix socket. This means the next attempt to start tissue fails since the Unix socket file exists already.

However, when tissue-web is run on the command-line and terminated with a Ctrl-C (SIGINT), it cleans up its Unix socket correctly.

This issue is likely because tissue is not handling the SIGTERM signal correctly.

(made with skribilo)