New preferences:
  extensions.torlauncher.socks_port_use_ipc (Boolean; defaults to true)
  extensions.torlauncher.socks_ipc_path (override default IPC path)
  extensions.torlauncher.socks_port_flags (SocksPort flags)

Also added support for the TOR_SOCKS_IPC_PATH environment variable.

Consistently use IPC to refer to Unix domain sockets.
Renamed preferences:
  extensions.torlauncher.control_port_use_socket is now
    extensions.torlauncher.control_port_use_ipc
  extensions.torlauncher.control_socket_path is now
    extensions.torlauncher.control_ipc_path
Renamed the TOR_CONTROL_SOCKET env variable to TOR_CONTROL_IPC_PATH.

Change _strUnescape() to throw and fix hex and octal unescaping.