Cleanup url and title update sequence

In normal navigation cases, url and title are written to database
but callback is not triggered. DBWorker emits tabChanged
from DBWorker::goBack or DBWorker::goForward.

Conflicts:
	src/declarativetabmodel.cpp
Align tabmodel unit tests to previous commit
Merge pull request #214 from rainemak/cleanupUrlTitleUpdate

Cleanup url and title callbacks from database