Rename Collection#sorted

[anandre]

Collection#sorted should be renamed to some sort of verb; "sorted" is an adjective and doesn't fit in with the rest of the method names, which are mostly verbs (I recognize that some is a loose fit, but it's coming from Array so...). Opening this issue to generate some ideas.

[vaporoxx]

Is this method actually needed? From what I can see, these two calls should be exactly identical:

collection.sorted(fn);
collection.clone().sort(fn);