Actionbar title not updated

When leaving the formula editor back to the script, the title in the Actionbar wasn't updated and still said "Formula Editor"

- the previous Actionbar title is now delivered by the ProjectManager (currentSprite)

- added Testcase to check the title in the Actionbar

Test: https://jenkins.catrob.at/view/Catroid/job/Catroid-Multi-Job-Custom-Branch/292/