Missing parenthesis fixed.
Missing bracket fixed.
Covariance function for a constant function implemented.
Polynomial covariance function implemented.
feval function improved to pass parameter d to the polynomial covariance function.
A mask composite covariance function implemented.
Scale composite covariance function implemented.
Matern covariance function with isotropic distance measure implemented.
Minor bug in matern covariance function fixed.
Minor improvement of matern covariance function.
Neural network covariance function implemented.
Piecewise polynomial covariance function implemented.
Merge pull request #3 from depet/gpml

Gpml