Crate ns_std_threaded

This crate provides a simple name resolver that uses lib's name resolution.

Unfortunately libc doesn't provide asyncrhonous name resolution for many reasons so we run requests in a thread pool.

For high-performance server applications this way is far from being performant, still it is the most compatible to everything else. So it might be used:

1. To provide maximum compatibility (i.e. good default for dev environment)
2. In applications where name resolution is not slow part
3. As a fallthrough resolver for ns_router::Router where more frequently used name suffixes are overriden with faster resolver for that namespace

Structs

Future	A Future returned from resolver
ThreadedResolver	A resolver that uses ToSocketAddrs from stdlib in thread pool