Merge pull request #104 from matfed/master

OpenAire+ integration
Removed Importers module.
Using MessageFormatter from slf4j
Support of keyword extraction from document's content, abstract or both content and abstract
Merge branch 'master' of git://github.com/CeON/CoAnSys
Merge pull request #105 from acz-icm/master

Extract keywords from abstract and/or document's content
Merge remote-tracking branch 'upstream/master'