Toolbar overflow strategy 1

completed by: Ezequiel Pereira

mentors: Martin Abente Lahaye

Related to http://bugs.sugarlabs.org/ticket/4257 we need a better strategy for toolbars that are too wide for the screen. The current list of buttons only works for button toolitems and not all toolitems. A palette, such as is found in Turtle Blocks might be a better solution. Submit a design for a new overflow strategy.