Added the first overlay of the tooltips, with some test data.

The tooltips now can:
1 - be moved around the canvas
2 - dynamically expand / retreat when a new tooltip is added.

Signed-off-by: Tomaz Canabrava <tcanabrava@kde.org>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Adds real support for ToolTips.

This patch changes the Event drawing so it can display tooltips. It is now
the responsibility of the item to show / hide a tooltip.

A bit of code-refactoring got on here too because I was using only
QGraphicsItem calls and I wanted to use a hover in / hover out event
to show / hide the tooltip.

Signed-off-by: Tomaz Canabrava <tcanabrava@kde.org>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Added a bit of documentation on how to use the ToolTips & removed 2 bad-api methods

Signed-off-by: Tomaz Canabrava <tcanabrava@kde.org>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>