preprocessor for analog device about ulnoiot-upy

[ulno]

Fixed with 6928514.

Here are two examples I used for testing:

from uiot import *

values = [0]*50
fill = 0
total_t = 0
total_h = 0

def my_median( v ):
    global values, fill
    if v is not None:
        values[fill] = v[1]
        fill += 1
        if fill==len(values):
            values.sort()
            fill = 0
#            print(values)
            return v[0],values[len(values)//2]
    return None

def my_average( v ):
    global total_h, total_t, fill
    if v is not None:
        h, t = v
        total_h += h
        total_t += t
        fill += 1
        if fill == 50:
            retval = total_h/fill, total_t/fill
            fill = 0
            total_h = 0
            total_t = 0
            return retval
    return None

d("dht11", "t", d1, filter=my_average)
#d("dht11", "t", d1)