PROSPECT-D added

This is a pre-release version!!!

I have added the PROSPECT-D model of Féret et al. (2017). The model is in essence the same PROSPECT as before, but with updated absorption spectra, and the addition of anthocyanins. PROSPECT has been re-written in Python (although the old FORTRAN version is still in the bindings), whereas SAIL is still a Python wrapper on the Fortran code. This module exposes both the PROSPECT model (both versions through the prospect_d method), as well as the possibility of coupling PROSPECT5 or D with SAIL (through the run_prosail method). I'm calling it a beta version because there's still documentation updates to be made, and some tests.

For more information on PROSPECT-D, see the following reference:
Féret, J-B., A. A. Gitelson, S. D. Noble, and S. Jacquemoud. "PROSPECT-D: Towards modeling leaf optical properties through a complete lifecycle." Remote Sensing of Environment 193 (2017): 204-215. DOI