- Upgrade to 1.4.3
    - Added swig dependancy for python module
    - Updated unbound.conf with new options
    - Enabled pre-fetching DNSKEY records (DNSSEC speedup)
    - Enabled re-fetching popular records before they expire
    - Enabled logging of DNSSEC validation errors
    - Overriding -D_GNU_SOURCE is no longer needed. This fixes DSO issues with
        pthreads