Allow requestURI with only parameters (changes included)

====
imported from sf tracker
id 860390
submitted by Paul McCulloch - paulmcculloch
http://sourceforge.net/support/tracker.php?aid=860390
====

Currently the requestURI attribute can be used in two ways:
1) Provide a URI that should be used when the user
wishes to view another page or to sort

2) Use an empty attribute ("") to indicate that the URI
that was used to render the page should be used, with
the addition of the <table> specific paging & sorting
parameters.

It would be convinent to be able to add extra
parameters to a request of the 2nd type, or to override
the existing value of some of the parametres.

This can be achieved (1.0-b2) by changing
org.displaytag.util.Href.java in the constructor:
public Href(String baseUrl)

replacing:
url = tokenizer.nextToken();

with:

if(baseUrl.startsWith("?"))
{
//support fake URI's which are just
parameters to use with the current uri
url = "";
}
else
{
// base url (before "?")
url = tokenizer.nextToken();
}

For this change to allow the overriding of exisiting
parametres bug 858888 must be addressed.

I'm not familiar with CVS, otherwise I'd submit a patch.