Get rid of all code defining or referencing t32.

Such code never made sense; it was all of the form

    t32 = 1L << 32
    if something < 0:
        something = t32 - something

which is a way to change negative integers into
gigantic positive integers greater than 4 billion, and
never made sense in context.  Possibly

        something = t32 + something

was intended, but that never made sense in context either.

In any case, `something` is invariably obtained from
struct.unpack using the "H" format code, and that never
returns a negative integer to begin with.