Remove SigIntMixin

This was meant mostly as an example, it doesn't justify its own file.

progress/helpers.py

@@ -1,28 +0,0 @@
-# Copyright (c) 2012 Giorgos Verigakis <verigak@gmail.com>
-#
-# Permission to use, copy, modify, and distribute this software for any
-# purpose with or without fee is hereby granted, provided that the above
-# copyright notice and this permission notice appear in all copies.
-#
-# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-
-from signal import signal, SIGINT
-from sys import exit
-
-
-class SigIntMixin(object):
-    """Registers a signal handler that calls finish on SIGINT"""
-
-    def __init__(self, *args, **kwargs):
-        super(SigIntMixin, self).__init__(*args, **kwargs)
-        signal(SIGINT, self._sigint_handler)
-
-    def _sigint_handler(self, signum, frame):
-        self.finish()
-        exit(0)