Gaufrette/core — pull request #41 by PedroTroller (2014-12-03 12:47:18+00:00)
Title: An adapter can describe it's behaviors

We will have a limitation concerning adapters that wraps others (for example `Cache` or `Safe`). These kind of adapter should have the same behaviors than the wrapped ones.
For example, `Cache` wrap two adapters. And It's behavior should be the intersection of behaviors of wrapped adapters.

| Adapter1 | Adapter2 | Wrapper |
| -------------- | ---------------- | ------------ |
| Content | Content | Content |
| Metadata | Checksum | |
| Size | | |