+ Add memcached stats input

Hi there,

I created a memcached stats input (https://github.com/tootedom/logstash_memcached_stats).  Just wondering if you'd be interested in adding it to the contrib or not.

Apologies if I should have opened this request via a jira ticket, but I was getting the following when attempting to sign up on logstash.jira.com
    
    {"genericErrors":["We are currently unable to complete your sign up.\nThere are no available licenses for JIRA."]}

Let me know your thoughts, and if/how I should write the associated documentation; if you are interested in pulling the change.

cheers
/dom