adding :deserialize-composites option to allow disabling composite deserialization

[ryfow]

I'd like to make use of the fact that AbstractComposite implements Comparable but I can't do that if composites are automatically converted into vectors. I suppose I could just use :byte-serializer and do the deserialization in the application but it's be handy to have the option in clj-hector.

[dinedal]

:+1:

[pingles]

Thanks- I've merged the changes and pushed the 0.2.10 release to Clojars. Sorry it took me so long to do it!

[ryfow]

Thanks.