Add a vim modeline so my tabs get converted to spaces
Add the option to disable a storage engine if needed

Use case: you have memcache installed, but don't want to use it.
Right now we'll try and connect to memcache, fail and then fallback
to file cache. This adds overhead since we're never going to actually
use memcached.
Throw a E_USER_WARNING error if we can't mkdir
Add usage to the README.md
Oops wrong variable/constant
Merge pull request #1 from scottchiefbaker/master

Awesome!  Thanks Scott