Write out net and turbulent fluxes to eval files?

[wwieder]

Currently NEE is the net sum of turbulent and storage fluxes, which is then used for GPP estimated in ReddyProc.

Latent heat and sensible heat just uses the turbulent flux measurements.

Discussion at our data meeting seemed to agree that the turbulent and net fluxes should likely be provided for eval files (with storage fluxes calculated as their difference), would allow users use the NEON data to investigate this scientifically.