getRootCategories(aspect) returns the root categories in a
      classification.
  
    Parameters
- aspect
- A string that represents the aspect whose root categories are to be returned.
Returns
Returns a list of CategoryTemplateNodes that represent the root category nodes for the specified aspect.
Example
      
<#list classification.getRootCategories("cm:generalclassifiable") as n>
  ${n.name}<br>
</#list>     
      
    
      The preceding code snippet would return output similar to the following:
Software Document Classification Languages Regions Tags
