Log Message:
Update p5-Date-Manip to 6.53:

Bug fixes

Date::Manip::Delta::cmp had a bug in it's comparison.  Ian Gibbs.

The secs_since_1970_GMT method was missing a test to see if it was
a valid object.  RT 111915

Time zone fixes

Newest zoneinfo data (tzdata 2016a)

Documentation fixes

Lots of typos fixed.  I was using podspell to do spell checking, but it was
discarding too much real text (which wasn't getting checked as a result).
Switched to pod2text which does a better job.  RT 110025