equals() and hashCode() for items

[mikaelstaldal]

It would be useful if the various Item classes implemented equals() and hashCode().

[reschke]

(work in progress)

[reschke]

@mikaelstaldal - do you want to check before I merge?

[mikaelstaldal]

@mikaelstaldal - do you want to check before I merge?

I used this library on my previous job, but not any longer (my new job does not use JVM stack). But nice that you fixed it, if I would find use for it again in future.

[reschke]

Thanks, and sorry it took so long.