IllegalStateException when type is an array

[DavidMhn]

When an object type is an array, for instance "type": ["string","integer"] The conversion fails with this stack

java.lang.IllegalStateException
	at com.google.gson.JsonArray.getAsString(JsonArray.java:226)
	at edu.uoc.som.jsonschematouml.generators.JSONSchemaToUML.analyzeProperty(JSONSchemaToUML.java:463)
	at edu.uoc.som.jsonschematouml.generators.JSONSchemaToUML.analyzeObject(JSONSchemaToUML.java:336)
	at edu.uoc.som.jsonschematouml.generators.JSONSchemaToUML.analyzeRootSchemaElement(JSONSchemaToUML.java:264)
	at edu.uoc.som.jsonschematouml.generators.JSONSchemaToUML.analyzeDefinitions(JSONSchemaToUML.java:754)
	at edu.uoc.som.jsonschematouml.generators.JSONSchemaToUML.analyzeRootSchemaElement(JSONSchemaToUML.java:269)
	at edu.uoc.som.jsonschematouml.generators.JSONSchemaToUML.analyzeSchema(JSONSchemaToUML.java:253)
	at edu.uoc.som.jsonschematouml.generators.JSONSchemaToUML.analyze(JSONSchemaToUML.java:219)
	at edu.uoc.som.jsonschematouml.generators.JSONSchemaToUML.launch(JSONSchemaToUML.java:171)
	at edu.uoc.som.jsonschematouml.ui.handlers.ConvertToClassDiagram$1.run(ConvertToClassDiagram.java:56)
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:63)

This line doesn't handle the array case:

JSONSchemaToUML.java:463
 else if(itemsObject.has("type") && itemsObject.get("type").getAsString().equals("string")) { 
```					

Note this case of type is conform to json schema type definition (at least in json schema draft v7):

"type": { "anyOf": [ {"$ref": "#/definitions/simpleTypes"}, { "type": "array", "items": {"$ref": "#/definitions/simpleTypes"}, "minItems": 1, "uniqueItems": true } ],