normalize MOUNTed URL if it includes "../" in URL-path
represent (MOUNTed) URLs as partial URLs if possible
convert all of URLs to full URLs
The special convListURICONV="+" means loading the default URICONV
configuration (no attrList in this case in the current implementation).
The attrList is a list of attributes names each may be postfixed
with an element name. A special attributes name "+" means the
default set of attributes. An attribute prefixed with "-"
character is excluded from the calculated set of attributes.
Another special convListURICONV="where:any" enables searching URL
to be rewritten not only in HTML tags but also