Code cleanup and bugfixes:

- Resolve threading deadlock when multiple watch request arrived at the same moment.
- Implement more graceful server exit.
- Reduce excessive logging.
- Fix unix socket clearing; until Sanic starts accepting Path for unix socket name.

cista/util/apphelpers.py

@@ -21,7 +21,6 @@ def jres(data, **kwargs):
 
 
 async def handle_sanic_exception(request, e):
-    logger.exception(e)
     context, code = {}, 500
     message = str(e)
     if isinstance(e, SanicException):