Equals, Tuples and Case-classes

This is mostly a quick tip (or opportunity for refactoring).

Most of Scala's built in classes implement a useful equals and hashcode. The very commonly used case-classes and Tuple classes are the examples that spring to mind. So this enables the following options:

1. // Assume Box is out of your control and you cannot refactor it into a case class
2. scala> class Box(val name:String, val minx:Int, val miny:Int, val maxx:Int, val maxy:Int)
3. defined class Box
5. scala> val box = new Box("mybox", 0, 0, 10, 10)
6. box: Box = Box@568bf3ec
8. // before:
9. scala> box.minx == 0 && box.miny == 0 && box.maxx == 10 && box.maxy == 10      
10. res3: Boolean = true
12. // after
13. scala> import box._
14. import box._
16. scala> (minx,miny,maxx,maxy) == (0,0,10,10)
17. res5: Boolean = true
19. // another box definition:
20. scala> case class Box2 (name:String, ul:(Int,Int), lr:(Int,Int)) 
21. defined class Box2
23. // case classes have nice equals for comparison
24. scala> box2 == Box2("a nicer box", (0,0), (10,10))
25. res6: Boolean = true
27. // but what if you don't want to compare names
28. scala> import box2._
29. import box2._
31. scala> (ul,lr) == ((0,0),(10,10))
32. res7: Boolean = true