Improves Ownable events (#1397)

* signing prefix added

* Minor improvement

* Tests changed

* Successfully tested

* Minor improvements

* Minor improvements

* Revert "Dangling commas are now required. (#1359)"

This reverts commit a688977.

* updates

* fixes #1392

* event tests added

* constructor event added

(cherry picked from commit af42c39)

Author: Aniket-Engg