Add access time and modification time support
Fix tests
Fix phpdoc and function scope

Fix phpdoc and function scope

Fix phpdoc

Remove useless doc and fix descriptions

Use 'part of adapter' instread of 'element'
Fix doc
Merge pull request #40 from Gaufrette/fix/phpdoc-and-scopes

Fix phpdoc and function scope
Merge pull request #39 from Gaufrette/feature/file-dates

Add access time and modification time support
An adapter can describe it's behaviors