Allow printing of all the metrics

[manish7294]

As of now, benchmarks only writes out timings to the output as the programme execute, but ideally it should have all the metrics(like Timings, Accuracy, etc. ) in the output, which are there being measured in method's benchmarking script.
Currently bash output looks like (It only shows timings):

	mlpack	shogun
iris	0.008097	0.008097
ionosphere	0.172063	0.172063

But I think it should be somewhat like (need not to be similar) :

Time	Mlpack	Shogun
iris	0.008097	0.008097
ionosphere	0.172063	0.172063

Accuracy	Mlpack	Shogun
iris	96.6667	96.6667
ionosphere	97.3245	97.3245

[rcurtin]

I agree, definitely this would be an improvement.