Remove dependancy between toolbar and notification plugin

[msamsel]

What is the purpose of this pull request?

bug fix

Does your PR contain necessary tests?

I hope so :)

This PR contains

• Unit tests
• Manual tests

What changes did you make?

• Made update to notification to skip section related to toolbar position, if toolbar position doesn't exists.
• Made some small changes in unit test to include toolbar in tests.
• Add few new unit test to test cases of editor without toolbar
• Add dependancy to clipboard plugin to use toolbar. It appears that earlier clipboard base on dependancy included in notification.

close #491

[jonnott]

+1 love it - let's get this baby merged ;)

[jonnott]

Will this be in v4.7.2 then? If not, how do we ensure it is...? ;)

[Comandeer]

Yes, it'll be a part of 4.7.2 release.