Implement toolbar actions (start all bricks, stop all bricks...)

[Daniele Lacamera]

Implement the toolbar actions.

When implementing the 'start all' function:
   * Visit the bricks list on the brickfactory
   * select a starting point
   * detect a network loop exception, which case should result in an error dialog explaining so (start all is not possible if there are network loops). There is already an exception in poweron method for that.

Also, eventually add quick toolbar buttons for delete and copy (like in context menu)

[Daniele Lacamera (o-root-danielinux-net)]

Closed in r17