constness issue in nose tests

Created by: siebenkopf

With the new constness initiative (see: https://github.com/bioidiap/bob.blitz/issues/6) there are some nose tests failing: https://travis-ci.org/bioidiap/bob.learn.mlp/builds/120843870 as they try to modify values that are const. Please review both the tests and also whether these values must be returned as const arrays.