mini-reporter: align numbers in summary and error output:

[jamestalmage]

This looks a little goofy to me:

Should they be aligned?

[sindresorhus]

Yes. I've noticed this too. Just hadn't gotten around to reporting it yet.

[sotojuan]

Hm this seems to be working for me in latest master already, can someone confirm?

[stefanlegg]

Looks to be aligned correctly in master, but not in the 0.14.0 release

[novemberborn]

Yea I made changes here in #737 which landed after 0.14.0 was cut.