Four and Five column format must be specified by the user, although it could be automatically estimated

So far, the user has two different functions to load/process score files, depending on the format. On the other hand, @amohammadi has implemented a way of automatically estimating the score file format: https://gitlab.idiap.ch/bob/bob.measure/blob/master/bob/measure/load.py#L315, so that the user does not need to specify the format anymore. I think, we should provide generic functions for similar tasks, too, i.e., having:

• bob.measure.load.scores(filename, ncolumns=None)
• bob.measure.load.split(filename, ncolumns=None)
• bob.measure.load.cmc(filename, ncolumns=None)

These functions should use the same way of handling ncolumns=None.