Add support for java.lang.Bool, Integer and Long classes

[qistoph]

This PR adds support for instances of

• java.lang.Bool
• java.lang.Integer
• java.lang.Long

Test cases created with:

import java.io.FileOutputStream;
import java.io.ObjectOutputStream;
import java.util.HashMap;

public class Creator {
    public static void main(String[] args)
    throws Exception {
        HashMap hm1 = new HashMap();
        hm1.put("key1", "value1");
        hm1.put("key2", "value2");
        hm1.put("int", 9);
        hm1.put("ing2", new Integer(10));
        hm1.put("bool", true);
        hm1.put("bool2", new Boolean(true));
        FileOutputStream fs = new FileOutputStream("hashmap-1.ser");
        ObjectOutputStream os = new ObjectOutputStream(fs);
        os.writeObject(hm1);
        os.close();

        HashMap hm2 = new HashMap();
        hm2.put("key1", hm1);
        fs = new FileOutputStream("hashmap-2.ser");
        os = new ObjectOutputStream(fs);
        os.writeObject(hm2);
        os.close();
    }
}

Tested with:

#!/usr/bin/python3
  
import sys
import logging

logging.basicConfig(level=logging.DEBUG, stream=sys.stdout)

import javaobj

#filename = 'creator/hashmap-1.ser'
filename = 'creator/hashmap-2.ser'
with open(filename, 'rb') as fd:
    jobj = fd.read()

pobj = javaobj.loads(jobj)
print(pobj)

[coveralls]

Coverage decreased (-0.3%) to 79.237% when pulling a2c0172 on qistoph:master into 1dc4427 on tcalmant:master.

[tcalmant]

Thank you for your contribution 👍
I've added the unit test plus the comparison operators to the loaded classes