ParaDNS Changes

1.3
    - Change cache to be global instead of per-resolver
    - Separate cache and resolver cleanups
    - Make timeouts and repeaters configurable

1.2
    - Support for ParaDNS::XS

1.1

    - Cache NXDOMAIN lookups according to RFC 2308
    - Allow timeout to be set ($ParaDNS::TIMEOUT)
    - Drop per-resolver timeout to 10 seconds