Wrong unpacking in receiveprop-decoder for floats

[spheenik]

in skadi/decoder/recv_prop/float.py you can find the following:

    def _decode_normal(self, stream):
        """
        Decode 'normal' float, which appears to be 11 low bits in a float
        multiplied by specific float-encoding-related values.

        Arguments:
        stream -- a Stream (skadi.io.stream)

        Returns a float.

        """
        s = stream.read_numeric_bits(1) # sign
        l = stream.read_numeric_bits(11) # low
        b = bytearray(0, 0, l & 0x0000ff00, l & 0x000000ff)
        v = struct.unpack('f', b)[0]

        # not sure this is ever called. what does bitshifting a float mean?
        if v >> 31:
            v += 4.2949673e9

        v *= 4.885197850512946e-4

        return v * -1 if s else v

which puts the eleven bits read in l into the bytearray b.
However, the third value put in, l & 0x0000ff00 will be zero all the time.

Proposed fix:
put (l & 0x0000ff00) >> 8 into the third byte.