Fixed a crash when re-using a SharedWidgetPtr with the init function
Fixed 'Checked and Unchecked triggers of Checkbox are emitted too early' (Issue #9)
Avoid sending an unchecked callback followed by a checked callback when trying to check a radio button that was already checked.
Make getSize of CheckBox return the size that includes the text (fixes #6)
Added a function in Grid to change borders of a given widget.