move Lwt-specific bits into their own directory
cleanup resolver code with fewer operators and opens
add Resolv.conf parser from Melange; needs porting to Lwt
move the portable resolver interface into lib, and the Lwt-specific portion into Dns_resolver

TODO: remove lib/Utils now
port Dns.Resolvconf to use Re_str instead of manual splits, and remove the Utils module as a result
add support for custom ports in nameserver entries.

unfortunately, MacOS X seems to have a different convention for this than *BSD, so I went with the *BSD one, which is also less insane.
instantiate a resolver specifically, to let apps choose how they resolve DNS (either resolv.conf or a manually specified NS, and eventually by iterative resolution)
modify odig to support new Dns_resolver
build lwt docs also
build Lwt doc also
expose more to_string functions in the Packet signatures.

This introduces a dependency on cstruct-0.5.1+
Add a dig-like tool that uses the resolver
being porting mldig to Cmdliner instead of the ad-hoc Arg
remove odig now that mldig works
mark mldig
note the TODO for the pattern match inexhaustiveness
mark 0.5.0
bump trunk to 0.5.1
remain compatible with 3.12.1

From: Haris Rotsos
update CHANGES