Added support for UPD/TCP communication to graphite

Graphite communication is now configurable to be either tcp or udp.
An attribute is added to the <graphite /> configuration tag that decides whether to use UDP og TCP when sending data to graphite.

Also includes a bug fix which adds a "\r\n" after each line sent to graphite in both UDP and TCP. The UDP part is untested though.
"protocol" needs to be optional to preserve existing configuration files.