Corrected issue with estimates for temperature and temperature-based npp.
Snow cover is now a function of temperature
Replaced precip model with trigonometric model proposed by /u/astrographer of reddit, fit to data by Baumgartner & Reichel (1975).
Added evaporation model to correct disparities between precip from Lieth (1975) and Baumgartner & Reichel (1975).
Modified precip model parameters to fit to original precip data used for Miami model.
Merge branch 'master' into gh-pages