MERGE: trunk> svn merge --reintegrate https://.../dutfoy (1792:1855)

distcheck ok.
BRANCH: created branch bayesian
test
Modify the Reference Guide (Bayesian Calibration)
Modified Bayesian Calibration sections (RG + UM) and added a Metropolis-Hastings one (RG)
Modified Bayesian Calibration sections (RG + UM) and added a Metropolis-Hastings one (RG)
Fixed ReferenceGuide/docref_B21_MetropolisHastings.tex. distcheck ok.