add new option: 'defaultParameters'
XSLT->getClean() and XSLT->setClean() methods are declared to deprecated and add new methods: ->setMustClean(), ->getMustClean()
add new method: XSLT->removeParameters()
add new methods: XSLT->getInstanceId() and XSLT::getInstance()
some changes in XSLT->render() method
move the test files in "test/test_1" directory and change