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

classpath/java/lang/Float.java

@@ -1,13 +1,33 @@
 package java.lang;
 
-public final class Float {
+public final class Float extends Number {
   private final float value;
 
   public Float(float value) {
     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 value;
   }
+
+  public double doubleValue() {
+    return (double) value;
+  }
 }