When dragging outside of the ruler, the ruler emits
a signal guideLineCreated which when connected to the
KoCanvasControllers slot addGuideLine will temporary 
activate the KoGuidesTool. This tool then positions the
new guide line corresponding to the mouse movement.
When the mouse gets released, the guide line is added
to the guides data provided by the canvas.
To add support for guide lines to an application one
has to do the follwoing steps:
1. when creating your rulers, connect the guideLineCreated 
signal with the canvas controllers addGuideLine slot.
2. In the canvas implementation, reimplement the guidesData
function to provide access to the guides data of the
applications KoDocument implementation.
3. In the canvas implementation call KoGuidesData::paintGuides
to paint the guides.
4. Profit!!! :-)


svn path=/trunk/koffice/; revision=825673