Introduce generic event handling.

Signed-off-by: johnmave126 <johnmave126@gmail.com>
Change API related class to fit the new event style.

Signed-off-by: johnmave126 <johnmave126@gmail.com>
Deprecate old LoginDialog. Export to good MVC style Login Screen.
This does not provide full functionality of Login Screen.

Signed-off-by: johnmave126 <johnmave126@gmail.com>