Assigns new w2tabs object to a panel
    assignTabs(panel, tabs)
    
    
        | panel | string, name of the panel | 
    
        | tabs | string or object, tabs to assign | 
    
 
Description
The first argument 
panel is the name of the panel. It can be one of the following:
    - top
    
- left
    
- main
    
- right
    
- preview
    
- bottom
Initially you can set a tabs object for the panel when you initialize it in the following way:
However, if you already have a w2tabs object created, you can assign it to the panel with assignTabs method. If second
argument 
tabs is a string, it will look for tabs in the global w2ui object.