Revert "Fixed seralization error in responsetransporter, when changes containing date's."

This reverts commit ccbcee8e55d25595f0a043939f331e240e501653.
Fixed templatedossier tests.

With the fix https://github.com/4teamwork/ftw.testbrowser/pull/17,
the ftw.testbrowser handles the checkbox now correctly, so some changes in the
templatedossier tests was necessary.
Add ftw.testbrowser to sources.
Merge pull request #470 from 4teamwork/deif-failfailfail

Cherry pick a fix from `master`.
Move task-query to its own module.

Closes #453.