MongoDBConnector changes:
 - added "gridfs-stream" module
 - mongoConnector.saveContent  -  added
 - mongoConnector.copyContentFromFile  -  added
 - mongoConnector.getContent  -  added
 - mongoConnector.getContentStream  -  added
WebServerE changes:
 - app.post('/setContent/..)  -  modified
Merge branch 'database' of https://github.com/winfel/wa_knowledge_structuring into database

Conflicts:
	source/Server/connectors/MongoDBConnector.js