initial impelemtnation of moon rise/moon set calculation. however it has some apparent bug as it is only accurate to within 6 or 7 mins
corrected slight calculation problem with moon rise/set times.
I also cleaned things up and added a calculation of the moon rise and
moon set for tomorrow since it isn't always the case that the moon
rises and falls on the same day.
Merge pull request #3 from zoglmannk/feature-3-moon-riseset

Added a feature to calculate moon rise and moon set times