Log Message:
Update from version 0.5500 to version 0.5900 (upstream version 0.59)

Pkgsrc changes:
- adjust dependencies
- adjust license

Upstream changes:
0.59   2010-06-29

- More packaging fixes. This release makes sure that POD only shows up in the
  right files. In 0.56 through 0.58, some POD in the wrong place confused the
  search.cpan.org POD display code, and the main module's documentation wasn't
  viewable.

0.58   2010-06-28

- Versions 0.56 and 0.57 did not build XS properly when installing.

0.57   2010-06-26

- Make DateTime::LeapSecond have the same $VERSION as every other .pm file.

0.56   2010-06-26

- The set_formatter() method did not return the DateTime object, and did not
  actually validate the value provided for the formatter. Based on a patch by
  Andrew Whatson. RT #58506.

- Improved docs on floating time zone. Based on suggestions by Michael
  Svoboda. RT #56389.

- Added mention of end-of-month algorithms to docs on DateTime math. Based on
  a patch by Michael R. Davis. RT #58533.

- License is now Artistic 2.0.