Added support for running a function before the draw() function of a widget, for example when a widget needs to fetch additional user informations that aren't provided by the metadatas

Updated Annotation controller to assign "selected" class to buttons when they get clicked on, for use in custom css.

Added a button to cancel Annotation creation and hide the widget on CreateAnnotation

Updated LatestAnnotation, CurrentSegmentInfobox, AnnotationController and AnnotationList widgets to use timerange to find the current segment when the corresponding option is used + CurrentSegmentInfobox now has an option for editing the current segment + LatestAnnotation now has a "Copy and edit" button that allows to use the text from the currently displayed annotation into the CreateAnnotation widget textarea