- make UBDrawingController::mActiveRuler private
- use guarded pointer to avoid dangling pointer dereferencing
- provide public accessor functions
- consider a ruler active only if it is visible
- Basically simulate a device release with the previous tool and a
device press with the new tool to correctly terminate the previous
action.
- Hide the eraser when switching to another tool.
This makes it possible e.g to use the colorPicker app in conjunction
with the compass.
Colors will still be updated when one clicks the pen or marker tools.
It's icon is temporary.
Behavior implemented:
1. Can interact with all items without showing items frames (but ToolBar shows).
2. Cannot move items, but can drag images.
3. Selected items appears deselected when Play tool chosen.
4. Play tool don't requires selecting of item before interacts.
5. Cursor looks like tool icon in text and image widgets (should be the same in any others widgets, but now in w3c is not).