Whitespace changes.
Adds a comma back into journal formatter registration.

This one somehow got lost. But it definitely belongs here.
Removes acts_as_tree from planning elements.
Changes recycle bin to be triggered w/ trash.

Previously, destroy! would do what destroy formerly did, and destroy
would move to trash. Now trash trashes stuff into the recycle bin and
destroy destroys from DB.
Removes obsolete validation.
Removes obsolete method override.
Fixes remaining spec for circular structures.
Updates changelog.
Removes obsolete spec.

Testing circular dependencies is part of awesome_nested_set. Also, this
test is rather bad catching StaleObjectErrors.
Merge pull request #256 from opf/feature/no_more_acts_as_tree

No more acts_as_tree in planning elements.
allow pes without dates.
specs. pes w/o dates not in aggregations.
updated parent check for pes w/o dates.
changelog.
introduces ajax triggered inline diff on work_package#show

The functionality itself is adapted from issue#show.

On the other hand, the diff is no longer rendered with the full url as the
link's href. Using the full url caused problems with selenium tests that
ran into problems with cross domain requests. This could have been fixed
by setting the application's host and protocol setting accordingly.
However, it is much cleaner to use a relative url. So for rendering the
diff inside the application the behaviour was alterd to use relative
url. The full url is now only used where it is absolutely necessary
(pdf, email).
more general implementation for diff view

This view should not be specific to issues/work_packages.

Using polymorphic_url will for now lead to paths like "/issues/5".
But once only work_packages exist this will no longer be a problem.
updates changelog
Merge pull request #255 from opf/feature/work_package_on_page_diff

Feature/work package on page diff
releases 3.0.0pre8
Add within step that includes invisible elements.