update javadoc api en.
modify javadoc lang; modify dao declare.
update design doc; add image folder.
update image.
fix bug: domain validate rule: a-label should converted to u-label and
then validate;
remove unused items;
add toString method.
Merge remote-tracking branch 'cnnic/dev' into HEAD

Conflicts:
	doc/rdap_apidocs.rar
Merge pull request #552 from forumbyr/master

update design doc; fix domain validate bug.