Open a response-socket at configured location, named hbro.pid, and start listening for commands
Close the response socket by sending it the command QUIT. Typically called when exiting application.
Listen for incoming requests from response socket. Parse received commands and feed the corresponding callback, if any.
Return the socket path to use for the given browser's process ID.
Send a single command (through a Request socket) to the given Response socket, and return the answer.