Merge pull request #515 from yqz1016/dev

Remove initialization of RDAP_LINK_TITLE
Merge pull request #29 from cnnic/dev

merge from cnnic
fix bug: domain validate problem;
update sql.
Merge pull request #516 from forumbyr/master

fix bug: domain validate problem;
update sql: remove default value for as.
Merge pull request #517 from forumbyr/master

update sql: remove default value for as.
add 501 to errorMessage and RestResponseUtilTest
Merge remote-tracking branch 'rdapmaster/dev' into dev