Don't use abbreviation 'mins' and 'minutes' in the same sentence.

I don't think saving three letters justifies the use of a non-standard
abbreviation.  If we really need to save letters, then the SI units would
be better and for most people to read.
Merge pull request #432 from hindessm/avoid-abbreviation-and-be-consistent

Don't use abbreviation 'mins' and 'minutes' in the same sentence.