Update README.md

Removing myself from group.
Adding Psr\Cache proposal
Adding intro
Adding intro
Adding intro
Header size mod
Headers changes
Adding credits
Adding credits
Adding credits
Removing Cache->setItems()
Removing a reference to setItem()
Adding changes from dlsniper
Update psr-cache.md
Update psr-cache.md
Update psr-cache.md
setItems does not accept CacheItem objects.
Empty() method to clear()
Merge pull request #1 from simensen/docblock

setItems does not accept CacheItem objects.
Adding memcached example