Suggestion to produce files needed to build the lookup index

This pull request is related to issue https://github.com/dbpedia-spotlight/dbpedia-spotlight/issues/153.

In order to generate the files needed to build the lookup index, I created a modified version of https://github.com/dbpedia-spotlight/dbpedia-spotlight/blob/master/core/src/main/scala/org/dbpedia/spotlight/util/CreateLexicalizations.scala.  ---  https://github.com/JulienCojan/dbpedia-spotlight/blob/testLookupIndex/index/src/main/scala/org/dbpedia/spotlight/util/CreateLookupIndex.scala (moved into index/ in order to read settings from  indexing.properties) .