Converts the specified file location to a URL.
When the passed string is a file pathname on the local system, it will be converted to a valid URL.
Example 1:
returns:toURL("C:\\xml\\some.xsd")
Example 2:"file:/C:/xml/some.xsd"
returns:toURL("http://www.myorg.org/xml/some.xsd")
Example 3:"http://www.myorg.org/xml/some.xml"
returns:toURL("xml\\some.xsd")
"xml/some.xml"