fix #611 Error when tab selection triggers refresh

When tab selection triggers a refresh of the seciton containing the @aria:Tab widget, an error is raised when trying to give focus to the widget, which has been destroyed in the mean time.
fix #601 Tooltip on aria:Icon widget

A delegate id is now added to the markup generated by the Icon widget, so that listeners to mouse events are correctloy called.

Close #601
fix #600 general.disable was not checked in aria.templates.LegacyGeneralStyle,

before using it.