add "snappable" grid

[omaitzen]

I don't know how common my perspective is, but in my years-long on-and-off search for a satisfactory image editor for macOS that takes less time to open than GIMP, one of my hardline feature requirements is a grid that is visible (as an overlay), resizable, and snap-to-able. From what I've tried of Seashore so far, the lack of this feature is the one thing preventing me from adopting it as my primary image editor.

Just putting this out there in case it is useful feedback. :)

[robaho]

There are guides - once you zoom in enough to make them visible - see attached, but there may be a bug as the color setting does not appear to work. The guides are not resizable or snap-to-able.

Thanks for the feedback.

[robaho]

I will address this in a future release.