Add a parser to Corese

• We desire to parse files containing the simple following format to describe a directed graph: node1;edge;node2

In order to add the new parser:

• In the module kgtool, create a package fr.inria.edelweiss.kgtool.simple_parser
• in the fr.inria.edelweiss.kgtool.simple_parser, add two classes called SimpleParserLoader and SimpleParserCallback.