Remove alternative php tags

Removes:
 * `<%` opening tag
 * `<%=` short opening tag
 * `%>` closing tag
 * `/<script\s+language\s*=\s*(php|"php"|'php')\s*>/i` opening tag
 * `</script>` closing tag
 * `asp_tags` ini directive
Shouldn't this `asp_tags` mention be removed?