Merged the slinkp-datetime-200007 branch: fix the DateTime(anotherDateTime) constructor to preserve timezones.

o This branch will *not* be merged to the 2.11 line, but *will* be merged
  to the trunk.

o Third-party products which depend on 2.11 but would like to start removing
  Z2 interfaces themselves can use this branch for testing.

Merge branches/slinkp-zopectl-exitcode-143813: Fixes bug 143813, zopectl should exit non-zero if child processes fail.

Second of three tests. Calling ViewPageTemplateFile's without any arguments worked so far. The version in zope.app.pagetemplate always requires one to pass in the view as an argument. Examples in the wild are found in plone.app.portlets.

Added a test for the first of three problems found in real life applications with the ViewPageTemplateFile