* Added 2 fields, p_selected_program and p_new_program, to the

* Added 2 fields, p_selected_program and p_new_program, to the
  input_thread_t structure, so that we may support multi programs
  streams.
* Modified inputs to take account of this change.
* Modified input_clock.c so that it doesn't refer to pp_programs[0]
  any more.

Now we should not refer to the first program, but to the selected
program. Functions to change the current program are coming.