Rework Language.__hash__

[moi15moi]

Close #19

[georgkrause]

@moi15moi Thank you for the patch! This looks valid to me. Can we add a test or two to actually verify the hashes are equal for the same language but different for different ones? I can take over the test, if you are not interested in working on it. But I'd say the examples posted in #19 are already sufficient.

[moi15moi]

Just to be sure that it is clear, before this patch, it we try to add a test to verify the hash is the same when the language is the same AND a test to verify the hash is different when the language isn't the same, the test would already pass due to object caching

The problem "only" happen when we use pickle to save the object. The problem may be reproductable with another way, but I don't know how.

So, how do you want to test it? With saving the object with pickle AND then comparing the hash or by comparing the hash of 2 Language object that have been created in the same process?

[georgkrause]

@moi15moi Can't we just set Language._INSTANCES to an empty dict after creating the first object to disable the caching?

[moi15moi]

Yes, that's also a option.

[moi15moi]

Done. Let me know if everything is right for you.

[moi15moi]

@georgkrause I was wondering if it would be possible to push a new version on PyPi (like 3.4.1) with this fix.

[georgkrause]

@moi15moi Good idea, done!