#4 xslt-style variables support

This one's long term. My feature request is that an xpath object could access paths from other objects, denoted by $name - as a first approximation to the xslt specs where you can use $variable/xpath .

Of course we need a way to add new variables obtained from an match() evaluation (which can also be taken from other variables).

keep in mind that $variable could be a nodeset or another xpath object. Also, I have a question. Can php.xpath nodelists point to nodes located in other xpath objects?