Use inproc for the Router
Log via an IPC socket. Remove temp sessions.
Refactor tests' Launcher to use logs via IPC.
Update the tests to use the new Launcher.
Use IPC for Circus sockets
Use an IPC socket for Escalator.
Fix Python 3 compatibility in test_startup
Add a fallback for IPC sockets on Windows.
Merge branch 'ipc_sockets' into develop. Fix #103