Convert a relative URL to an absolute URL.
str = resolveurl(baseurl_str, embeddedurl_str)
An absolute URL built from the base URL and the embedded URL.
Supersedes urlbase
@CODE
"output.txt" << resolveurl("http://www.abcd.edu/x/y/z.html", "../gif/img1.gif")
<< "\n";
prints out:
http://www.abcd.edu/x/gif/img1.gif