add 10us to detect a valid 0 or 1
changed the delay before waiting for incoming data from 40 to 25
DHT22 appears slower to react than DHT11, so modified timings.
Also some calculations.
All values now reported normally. Cleaned up source code. Added contributor name into headers and readme.
Some minor bug fixed.
Merge pull request #6 from Dessimat0r/dht22_tunning

DHT22 finall timming fixes. Other small fixes by Dessimat0r
get out the beta label
Make an 0xFF and to sum
some times it can be bigger than 0xFF and it will trigger an checksum error