Allow TAdvToolBar to be resized at runtime

Ability for a user to resize a docked (primarily) and undocked toolbar at runtime, for example by dragging on the right handle.

The use case is where the control(s) contained on the toolbar are things like edit boxes for search strings/UR:Ls etc, where the developer does not want to dictate to the user how long those should be,

Particularly I am still working with the Office 2003 UI style. I am not sure what challenges this has for the ribbon toolbar style, but I would like some similar capability available when I convert to ribbon.