drop any default required version for EUMM
AutoVersion: lazy loading of DateTime

The AutoVersion plugin now loads DateTime only when needed. This will
reduce the amount of code compiled during `dzil listdeps`.

DateTime 0.44 is added explicitely in dist.ini.
TODO: AutoVersion should declare DateTime 0.44 as a 'develop' prereq.
NextRelease: lazy load DateTime
changelog entry for DateTime lazy load
delete tempdir_root (usually tmp) at the end of tests