Dont encapsulate tpls that are nested in other tpls.

* findWrappableTemplateRanges was collecting all templates for
  encapsulation.  However, nested templates need not be processed
  since the outermost templates are wrapped and only the outermost
  template transclusions can be edited.

* This eliminates problems downstream in encapsulateTemplates
  that attempts to detect overlapping and nesting of adjacent
  templates.

  - The existing code relied on sorting template ranges
    based on template about-ids -- the assumption was that
    these about-ids are assigned in wikitext source order.
    But, this assumption is violated for citation extension
    uses which are processed after all toplevel text is processed.

  - A better and more robust sort order would be use tsr[0] value
    of the opening template element.  However, tsr[0] is not
    available for nested templates, but it turns out we dont need
    to process them anyway.  So, yay!

* Fixes RT error on en:Allegations_of_tourist_apartheid_in_Cuba

Change-Id: I155a38cb6cc1e87ab0283b3cd8fd1d70151fe7d4