Parses a NIML string to a raw NIML tree-like structure
Parameters:
s: bytearray :
string to be converted
i: int :
Starting position in the string.
By default None is used, which means that the entire string is
converted.
Returns:
r: the NIML result. :
If input parameter i is None then a dictionary with NIML elements, or
a list containing such elements, is returned. If i is an integer,
then a tuple j, d is returned with d the new starting position and a
dictionary or list with the elements parsed so far.