Allows for middle click to be used to drag around the room canvas.

Clicking within the edge of a room object allows it to be resized by dragging once the object has been selected.

Description

General improved motion allowing for improved ease of use.

Pressing and holding middle click allows for the room canvas to be scrolled around, as well as for the margins to be expanded upon reaching the edge, allowing for areas previously out of bounds to be edited.

Once a room object is selected, clicking on it again near the edge will allow it to be dragged and resized (shift to increment by 0.5 or ctrl to increment by 0.1 in scale respectively).

Changes the control key to function more like a removal from any grid snapping (1x1), shift functions as it did before.

Pressing X/Y will flip selected object (invert X/Y scale)

Caveats

This is a draft - while the canvas dragging feels fine, attempting to resize some objects will freak out and grow exponentially.
Generally, drag resizing objects is the only really buggy part. I think it may be best to redo a lot of it and make it more like resizing in gamemaker studio, where the margins of the selected object's sprite are shown in an outline when it's clicked - that would probably make the math for resizing a bit more reliable as well.

Notes

I don't believe that I included any previous room editor changes that I made in separate PRs (making new room create code with the + button, stopping camera from returning to origin when objects are deleted), but if those are still in this feel free to tell me to get rid of them.

Thanks!