Ability to specify exact dimensions / snap to grid

[verglor]

It would be very useful if it was possible to specify exact size of shapes (especially text boxes and rectangles).

My use case is to create rectangle and inverted text box and I want them to be the same width, but I can only do it roughly by eye.

Alternatively snapping to grid would make things much easier too.

[MultiMote]

Will do 👍

I would also like to implement the alignment functionality as in some way similar to Inkscape.

[MultiMote]

Added position controls. Width and height currently displayed only for stroke objects. Changing size for other type of objects is a bit tricky, I will think how to implement it later.