Update pressure calculation to use equations from BMP datasheet instead of wikipedia.
Merge branch 'master' of https://github.com/adafruit/Adafruit_BMP085_Unified

# By Tony DiCola
# Via Tony DiCola
* 'master' of https://github.com/adafruit/Adafruit_BMP085_Unified:
  Update pressure calculation to use equations from BMP datasheet instead of wikipedia.