observations: metric is float|int
Merge branch 'master' of /home/martn/code/git/depot/pyDVar
Minor modifis to test routines in modelCovariances
Added precondStaticObsJTerm (3D-Var context)
Added test routine to precondJTerm.py
Multiple inheritance for precond + filtering in B
Added BkgJTerm (no preconditionning)