Change --eval option default and Various fixes

Change defaults, clean unused options for histograms.

Fix bob.bio.base#112 (closed)

mentioned in merge request bob.bio.base!161 (merged)

assigned to @tiago.pereira

@tiago.pereira could you please give this a review?

I will review this in the next hours.

I'm in another task now.

Cheers

LGTM

Thanks

mentioned in commit cb3964bd

merged