Changed variable type to int to display squares instead of rectangles

Summary:

On the left there's the old applet and on the right mine after only changing dotSize from real to int. All squares, not rectangles.

Reviewers: ngraham

Reviewed By: ngraham

Subscribers: davidedmundson, plasma-devel, ngraham, gladhorn

Tags: Plasma

Differential Revision: https://phabricator.kde.org/D14377