Switched to using zhash_first/next iterators for tuples

Much nicer...! I really like using this iterator style, keeping the
cursor context in the collection.
Adding service name for tracebilty
Revert "Feature: Added more syslog functionality to zlog"

This reverts commit b289d0622e7ce10cbcb5d6e9e13eb0bb6dc60119.

Mostly because complex constructors are an anti-pattern; it is
nicer to configure an object by setting properties on it. Also
because zlog was abstracted over syslog, and this change breaks
the abstraction and makes it specific to syslog.
Merge pull request #516 from hintjens/master

Minor improvements