added get_terms_images queue

fetches for localhost:5000/terms all dbpedia imagery available
and stores all urls in a single elasticsearch document

http://localhost:9200/beek/images/dbpedia

accessible on http://localhost:5000/images

{
  "cities": {
    "Amphipolis":
"http://commons.wikimedia.org/wiki/Special:FilePath/2011_Dimos_Amfipolis.png",
...
}