"Touching mouse pointer" always returns false when the sprite is hidden

[rachel-fenichel]

Expected Behavior

In Scratch 2.0 it returns true if it's over the sprite, even if the sprite is hidden.

To test, add and run these blocks:

Then hide the sprite, mouseover it, and show it again. It should have moved.

[thisandagain]

The problem appears to be that hidden sprites return dimensions of 0,0.

[thisandagain]

Moved to scratchfoundation/scratch-render#284