Experiments comparing GPEDA and CMA-ES in 2D

opt_gpeda - support for covSEard covariance function, too, model
            parameters should go here instead of modelInit.m
optimization_test2d.m - added restart and rescale conditions
gpeda   - only comment
modelInit - lik parameter is set
sampleGibbs - thresholds are tested in vice-versa order:
          [0 0.0001 ...]