added XContentWriteable  to be able to return XContent  as  json
used in  a    content  negoiation example  to sample
doco on execute
HitViewHelper that wraps ES hits objects to make them
easier to use in html templates
Changed object indexted to be an  article rather than a   thing
Article has a html attachement. Unfortunately had to add attachement plugin jars  to  git.
TODO: figure out how to install ES plugins through this plugin
Uses hit  view helper  in  template
Added page that shows article content
Added highlighing of results.
doco for hithelper, writeable, turn  off http interface, plugins
commented out  http.enable = false setting
doco for hithelper, writeable, turn  off http interface, plugins