Add .fill(array, value) function to arrays module

[#52401271]
Energy2D: Provide easy access to part's shape properties

[#52401271]

Instead of:
var rect = getPart(1).rectangle;
rect.x = 2;
getPart(1).rectangle = rect;

now we can simply call:
getPart(1).x = 2;
Energy2D: Reset simulation arrays when part properties are changed

[#52401271]

Except temperature and velocity to provide nice interactivity.
Energy2D: Expose .getPart(i) to Scripting API, add simple example

[#52401271]