Ctrl-C handling: sends SIGINT to process on receiving end of stdout pipe. If no pipe, Ctrl-C exits akt. Also, akt exits when the process on the receiving end of the stdout pipe exits. NUL input characters (Ctrl-@, Ctrl-` or Ctrl-space) are now passed through to output rather than being used to exit akt. Miscellaneous code cleanup. Bumped version to 1.1.