Potential for uncaught null exception

[pjhenning]

Hello, it is possible to construct a Concept value, via the first constructor, which gives an object with no value for the pos field:

WS4J/src/main/java/edu/uniba/di/lacam/kdde/lexical_db/data/Concept.java

Lines 12 to 14 in 44589e7

	public Concept(String synsetID) {
	this.synsetID = synsetID;
	}

but code elsewhere that operates on Concept objects will assume that the pos field has been populated:

WS4J/src/main/java/edu/uniba/di/lacam/kdde/ws4j/similarity/LeacockChodorow.java

Line 60 in 44589e7

if (concept1.getPOS().equals(POS.NOUN)) maxDepth = 20;

which can result in a runtime exception.