Use already-defined constants from pywin32
note TERM-related failing tests on windows
- potential strategy to fix at https://trac.torproject.org/projects/tor/ticket/9330#comment:11
note INT-related failing tests on windows
- potential strategy to fix similar to https://trac.torproject.org/projects/tor/ticket/9330#comment:11 but using CTRL-C for SIGINT
- also probably requires python fix for http://bugs.python.org/issue18040
use Windows JobObjects to have all children killed when the parent process dies unexpectedly