new: ``sact.epoch.Time`` can now be instanciated directly from a string, trying predefined format and even using ``dateutil`` to the rescue.

Note that ``dateutil`` can parse timezone information but ``strptime`` can't, so
``strptime`` formats are tried only if you provide a ``hint_src_tz``.
fix: pkg: ``README.rst`` wasn't parsed by tests, and thus corrected failing test and added a few. @minor