* fhandler.h (fhandler_tty_slave): Declare new methods.

* fhandler.h (fhandler_tty_slave): Declare new methods.
* select.cc (fhandler_tty_slave::select_read): New method.
* select.cc (fhandler_tty_slave::ready_for_read): Ditto.
* select.cc (verify_tty_slave): New function.
* fhandler_termios.cc (fhandler_termios::line_edit): Empty input
buffer on signal.
* fhandler_tty.cc (fhandler_tty_slave::read): Check for input data
after reading from pipe. Reset event if input pipe is empty.
* tty.h (class tty): Allow creating events with manual reset.
* tty.cc (tty::get_event): Use manual_reset flag.
* tty.cc (tty::common_init): Create input_available_event with
manual reset.