[PATCH] Implement DNS cache service

Here is an implementation of DNS cache service.
Pipe and service code are heavily borrowed from dhcp client service.
How it works:
dnsapi.dll is registering a service and opens a pipe for requests.
When a request comes puts in (or reads data from) cache.
Use pipe to query/add records from DNSQuery_W when cache flag is not cleared.
If service pipe is not available or item doesn't exist in cache, then normal query is performed.
Please test, review, comment.