Bug fix for lsb_queueinfo()

- The LSF API docs state that calling lsb_queueinfo with queues=NULL and
  numQueues=0 returns an array containing all queueInfoEnt structs and
  numQueues will be set to the size of the array.
- The LSF API docs state that calling lsb_queueinfo with queues=NULL and
  numQueues=1 returns a queueInfoEnt struct of the default queue
- Change the typemap of char ** to allow for NULL by passing in Py_None
- Add the ability for lsb_queueinfo to return an array of queueInfoEnt
  struct.
- Without this patch the SWIG generation casts the pointer to
  the array from lsb_queueinfo to a single struct.

- Example Code:
  -------------
  from pythonlsf import lsf
  lsf.lsb_init('myapp')
  queue_names = None
  num_queues = lsf.new_intp()
  lsf.intp_assign(num_queues, 0)
  queue_data = lsf.lsb_queueinfo(queue_names, num_queues, None, None, 0)
  all_queues = lsf.queueInfoEntArray_frompointer(queue_data)
  for i in range(0,lsf.intp_value(num_queues)):
      print(all_queues[i].queue)