## change / DiceKriging 1.1

April, 15

1. Addition of an option "isotropic", building isotropic covariance kernels from tensor-product ones.
Technically: 
- a new class "covIso" has been created, 
- the existing method "show" has been extended to this class,
- the functions "covMatrix", "covMat1Mat2", "covMatrixGrad", "covVector.dx", "covParametersBounds",  are now implemented as METHODS.

2. covAffineScaling, with 2 knots per dimension. The analytical gradient has been implemented.

