Add types to graph event

[WikKam]

Currently, event from graph (adding new node/edge, deleting, clicking, hovering, etc) are not typed, we should include those types

[Wokstym]

Work has been started #15

[Wokstym]

TODO:

• add event type (Added click event type support #15 (comment))
• investigate items type in SingleClickData (Added click event type support #15 (comment))