XML parser ignores processing instructions

[Martijn Pieters]

Although BeautifulSoup includes a ProcessingInstruction element, the LXML xml parser ignores these completely:

    def pi(self, target, data):
        pass

This is easy enough to remedy; apart from importing ProcessingInstruction all the method has to do is:

    def pi(self, target, data):
        self.soup.endData()
        self.soup.handle_data(target + ' ' + data)
        self.soup.endData(ProcessingInstruction)

Can this be added?