QueryOnClickWizard - tbar icon order, default style and cursor

[adube]

QueryOnClickWizard minor enhancements :

• have the icon added as the first element of the toolbar (after the default ones)
• have a default iconCls property set in the toolbar stylesheet file
• change the mouse cursor for the "arrow" (default) when query widget is active

[adube]

r1031, featuring :

• all the above enhancements
• a new "displayClass" option now supported by the QueryOnClick widget in order to have the QueryOnClickWizard widget create one that has its own unique css "class", thus allowing to have a unique cursor for the widget.
• documentation updated

Done.