Make Jasperreports-Integeration depend on latest jasperreports lib

As suggested in http://wicket-users.markmail.org/thread/c7yoas3b7ckw3xzq I changed jasperreport dependency to net.sf.jasperreports to have actual release 5.1.0.

Also changed the <object> tag in SimplePdfPage to explicit closing for correct rendering in wicket.