factored out creating unit-class columns from readNcdfDataframe
to asUnitsDataFrame. Users should call now
readNcdfDataframe(...) %>% asUnitsDataFrame()
REddyProcNCDF 1.1.4
moving netCDF related functions from REddyProc 1.1.3 to this new package
automatically choosing between alternative backends RNetCDF and ncdf4,
using the one that can actually be loaded
cleaning function arguments
fileName includes directory, removing Dir.s argument
simpler argument names (not include type information)