Support long numbers

[ilyanep]

This JSON Schema:

        "version": {
          "type": "integer",
          "minimum": -9007199254740991,
          "maximum": 9007199254740991
        },

Is turned into this XSD:

         <element name="version">
            <simpleType>
               <restriction base="int">
                  <minInclusive value="1"/>
                  <maxInclusive value="-1"/>
               </restriction>
            </simpleType>
         </element>

Instead, I believe you could use the XML type long and use Longs in the java that reads in those mins and maxes.