BASGRA ryegrass and N limitation

This is the first upload of a version of BASGRA with N limitation.
- the 'winter' code is left out via precompiler switches
- ryegrass as opposed to the Timothy version of the model
- soil model is similar to that used in the forest model BASFOR
- the calibration of this version uses the adaptive Metropolis algorithm
- likelihood calculation using data min/max has been left out for now.
- this version requires various Oensingen datafiles which are not
currently included in this 'public' respository.
BC/data_calibration_Oensingen_2005_2007_noN.txt
input/OE_daily_weather_2005_2007.dat
../Oensingen/OE_doyharv_2005_2007.csv
../Oensingen/OE_fertilization_2005_2007.csv
- if the R code run_BASGRA_Oensingen.R is run a plot similar to
ryegrass-plot.pdf should be created