src/bin/d2/d2_lexer.ll
    Added regexp for ddns-domians, key-name,
    dns-servers, hostname

src/bin/d2/d2_parser.yy
    Added tokens and rules for ddns-domains,
    key-name, dns-servers, hostname

src/bin/d2/parser_context.h
src/bin/d2/parser_context.cc
    Added contexts FORWARD_DDNS, REVERSE_DDNS,
    DDNS_DOMAINS, DNS_SERVERS,

src/bin/d2/tests/testdata/d2_cfg_tests.json
    Changed logic-errors to syntax-errors