register, login, some search function

changes:
* register.
* login;
* search jids by cellphone number;
* search jid, nickname, photo by cellphone number or email.
*write cellphone number or email into vcard, vcard_search when register.
better to store it in a file and then [send this file as response](http://ninenines.eu/docs/en/cowboy/HEAD/guide/resp/#sending_files)