[kde-guidelines] Styleguide: Check boxes

[Aurélien Gâteau]

I updated the check boxes section in 
http://techbase.kde.org/Projects/Usability/HIG/Form_Label_Alignment#Checkboxes
with fresh screenshots.

I added a link to this section on 
http://techbase.kde.org/Projects/Usability/HIG/Check_Box#Guidelines

I also took the liberty to group the check box guidelines in 3 separate 
sections. I think that makes them easier to read, hope you don't mind.

Aurélien