Update documentation for headless apps: headlessservice, headlessserviceui, xandos, and xandosdroid.

    * NOTE: these changes are done directly to the generated qdoc and must be integrated ASAP into the
      original qdoc.
Merge pull request #160 from johodgson/topic_gh_pages_pull_headless_samples

Update documentation for headless apps: headlessservice, headlessservice...