Startting to records my developing task in android world!!

1. add a decription text telling how to add one new command in busybox adn how to set up dhcp4, dhcp6 server

2. add a passwordcheck daemol for any app wants to own a usercheck at the start of being started, this daemol is called in its caller onCreated() function, so it will repsent the caller's layout file as its background, and it's logic is simple: only have the correct pwd, it' will enter the caller app, otherwise ,it will hold on the login interface.