add a bunch of classes to classpath and flesh out a few existing ones

classpath/java/lang/Double.java

@@ -7,6 +7,26 @@ public final class Double {
     this.value = value;
   }
 
+  public byte byteValue() {
+    return (byte) value;
+  }
+
+  public short shortValue() {
+    return (short) value;
+  }
+
+  public int intValue() {
+    return (int) value;
+  }
+
+  public long longValue() {
+    return (long) value;
+  }
+
+  public float floatValue() {
+    return (float) value;
+  }
+
   public double doubleValue() {
     return value;
   }