[Feature] Support multiples of each event handler

[anderoonies]

Is your feature request related to a problem? Please describe.
When trying to add event handlers for specific elements, mouseDownMethod won't work since it overwrites the global mouseDownMethod. This means any reusable component can risk accidentally breaking other code.

Describe the solution you'd like
mouseDownMethod etc. can just add to an array of handlers that is iterated through

Describe alternatives you've considered
Creating a new graphics context would be messy, but might work.
Directly interacting with the canvas would also be a mess.