[master] Merged trac5073a (option 43)

diff --cc doc/guide/dhcp4-srv.xml
Simple merge

diff --cc src/bin/dhcp4/dhcp4_srv.cc
Simple merge

diff --cc src/bin/dhcp4/dhcp4_srv.h
Simple merge

diff --cc src/bin/dhcp4/tests/config_parser_unittest.cc
Simple merge

diff --cc src/bin/dhcp4/tests/get_config_unittest.cc
Simple merge

diff --cc src/lib/dhcp/std_option_defs.h
Simple merge

diff --cc src/lib/dhcp/tests/libdhcp++_unittest.cc
Simple merge