add combo extract to replace Extract2 Extract3...
update pom
update filecache to more useful
update ignore test
comments in english
update  comments
complete extension comments in en
bugfix: rawhtml do not work
update comments
update comments of spider
closable
update comments
update comments for selector
webmagic-core
complete all comments
update readme
update default readme to English
update docs
readme
update readme: and javadoc url