add future attribute to dns requests

[Vizonex]

What do these changes do?

This PR Fixes #168 and the bandage bottleneck witnessed earlier. It will help optimize when ctypedef callbacks are applied.

Are there changes in behavior for the user?

Is it a substantial burden for the maintainers to support this?

Related issue number

Checklist

• I think the code is well written
• Unit tests for the changes exist
• Documentation reflects the changes

[Vizonex]

I'll be back later this evening or tomorrow to explore other ideas on how we can safely get around this reference bug. My Second idea was subclassing winloop.loop.Future and then using it to hold the NameInfoRequest and AddrInfoRequest until they are ready to be called and finished off. That way this annoying problems will stop existing.

cdef class VizonexsMiraclePill(Future): # I will always be funny, you cannot stop me >:)
     cdef:
           NameInfoRequest nir

I think I'll coin them NameInfoFuture and AddrInfoFuture :)

[Vizonex]

Job complete 3.14t has a 50/50 chance but for what it's fault is is unrelated to DNS so I'll let it pass for now.