Send metrics to more than one Collectd server

Hello,

Current Collectdout sends metrics to only one server.
If you want to send to more than one Collectd server, you can create 2 instances of Collectd. This is not the best way.

I send you this PR to configure the Collectd object to send to any number of Collectd servers you want.
Older syntax still works (for compatibility - I check the `typeof(arg 2)` )
New syntax is to have arg2 as an array of ['host', port] and arg3 is ignored.

Regards