Following functions/methods have been add both to toolbar and item_proxy:
bool istoggle() const; ///< Returns true if the tool style is toggle.
bool toggle() const; ///< Gets the tool toggle state (only if tool style is toggle).
item_proxy& toggle(bool toggle_state); ///< Sets the tool toggle state (only if tool style is toggle).
std::string toggle_group() const; ///< Returns the toggle group associated with the tool (only if tool style is toggle).
item_proxy& toggle_group(const ::std::string& group); ///< Adds the tool to a toggle group (only if tool style is toggle).
This patch has 2 new features:
1- new option at constructor to enable creation of detached toolbar from
his parent, this enable the use of toolbar anywhere and the size can be
controlled by a layout manager.
2- add a new option in order to enable to place buttons at right part,
the widget has a new method go_right() after calling it, every new
button is right aligned.
Both changes don't break compatibility with old code.
