Memcached restart connection

[ItaloG]

Context

When mencached server receive many request it closes and return the error:

MemJS: Server <memcached:11211> failed after (2) retries with error - socket timed out waiting on response.

Mencached do not a throw a application error, so the application not auto-reset.

Need to be implemented a connection restart at Mencached adapter (cache-server.ts) on get, set, replace and delete functions.

[lucassm02]

Closed in #57