uidesigner: extended the snap-to-grid options

We now have a range of 1-10.
uidesigner: designer's Form property now has the exact class type
uidesigner: Now has an experimental "visual grid" on designer form.

This grid can be toggled on or off. Because it is experimental and still
a ongoing feature, there are currently some limitations:

 - Grid toggle status is not saved between sessions
 - Grid color is not yet configurable
 - Grid size can only be between 1-10