new useful urlread-urlreadv

function urlreadv solves most of the "Error downloading URL" problem caused by "urlread"

urlreadv Returns the source code of a URL as a string.
Syntax:
html=urlreadv(URL);
Description: urlreadv is a function based on java,it solves some
problems of the function "urlread",such as "Error downloading URL" and
avoid unreadable codes or gibberish while loading source code that contains
Chinese charcaters