Port observation of RDT and TH on view viewStatic were accidentaly removed

with backward compatibility with 2.0

'date_levee' can now be forced

SeuilETERTM is only for Rendement and Diagnostic

if false, there is no water stress, and FTSW = 1.0

- to use vle.recursive
- update reading of parameters (robust to R)
- and update vpz

rather than relying on function:
(Hcc_C1 - Hpf_C1 ) / 100.0 * da_C1 * ( 1.0 - TC );

begin date is now different from simulation_engine.begin

- use relative dates rather than absolute dates
date_TT_F1, data_TT_M0, date_TT_M3

- Hini (resp da, Hcc, Hpf) can be given and provide both
Hini_C1 and Hini_C2
- Hini represents the ration [0, 1] between Hpf and Hcc

The dynamic is now located into vle.discrete-time

 [@Andrianasolo2014]

All parameters have to be given in vpz.