src/bin/d2/d2_cfg_mgr.cc
    D2CfgMgr::parseElement() - now handles tsig-keys

src/bin/d2/d2_config.h
src/bin/d2/d2_config.cc
    TSIGKeyInfoParser and TSIGKeyInfoListParser now
    derive from SimpleParser

src/bin/d2/d2_lexer.ll
    Added algoritm, digest-bits, secret regexps

src/bin/d2/d2_parser.yy
    Added ALGORITHM, DIGEST_BITS, SECRET tokens
    Added rules for "tsig-keys"

src/bin/d2/parser_context.h
src/bin/d2/parser_context.cc
    Added contexts: TSIG_KEYS, ALGORITHM, DIGEST_BITS, SECRET

src/bin/d2/tests/d2_cfg_mgr_unittests.cc
    Revamped TSIG key tests

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