added support for subtypes, serviceDomain, parentDomain and instance

[wesleytodd]

See #2, #3, #5.

I tried to make this NOT a re-write, but clearly did not succeed :)

Let me know what you think!

[mafintosh]

I'll refer this to my local mdns advisor, @watson.

[wesleytodd]

Ok, so some of the changes I made here are actually causing more changes for the PR to this: watson/bonjour#1

If @watson is alright with that that it will be alright to merge this, but lets wait on this until I can integrate there and @watson approves, sound good? :)

[watson]

@wesleytodd The stringify function shouldn't take more than a single optional sub-type.

If a service have two sub-types it should be advertised as 3 different PTR records. E.g. a tcp http service Named Foo with the subtypes "Bar" and "Baz" will generate the following PTR records:

• _http._tcp.local. PTR Foo._http._tcp.local.
• Bar._sub._http._tcp.local. PTR Foo._http._tcp.local.
• Baz._sub._http._tcp.local. PTR Foo._http._tcp.local.

So a single record do never contain all of the sub-types.

[wesleytodd]

@watson Totally forgot about that conversion we had. Agreed and will add that to my list of changes!

[watson]

@wesleytodd ups, messed up the PTR records above - the instance name is of cause not part of the PTR record names. I've updated the comment to show the full PTR records

[watson]

@wesleytodd the general rule is that you should be able to take the output parse() and give as input to stringify() and vice-versa.

Also, parse() should be able to parse the following strings:

• _http._tcp.local.
• _http._tcp.example.com.
• _http._tcp.Xyz.example.com.
• Foo\.Bar\\ Baz._http._tcp.local.
• Foo\.Bar\\ Baz._http._tcp.example.com.
• Foo\.Bar\\ Baz._http._tcp.Xyz.example.com.
• Foo\.Bar\\ Baz._sub._http._tcp.local.
• Foo\.Bar\\ Baz._sub._http._tcp.example.com.
• Foo\.Bar\\ Baz._sub._http._tcp.Xyz.example.com.

Am I missing something?