add gem badge

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use experimental daybreak database

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fix daybreak adaprter

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update readme

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update daybreak adapter

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add links

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update readme

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readme clarify thread safety

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First round of set if not exists

- added #create specs ( with and without expires )
- added #create to Defaults, Proxy, Transformer
- implemented #create for redis adapter
Removed explicit return from redis
Implemented #create for both memcached adapters
Implemented create for sqlite
Fixed the method signature of create
removed explict returns

![i still think explicit return improves readability](http://i.qkme.me/3sjtp0.jpg)