[*]: update the CHANGELOG

[!]: "php": ">=7.0" v2

[+]: optimize "_do_never_allowed()"

[+]: use new version of "Portable-UTF8" (voku/portable-utf8)

[*]: use "error_reporting(E_ALL)" for tests

[!!!]: prevent UTF-7 charset attacks + optimize "style"-attribute pro…

…cessing

-> https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet

[+]: fix for HHVM v2

[!!!]: fix "data URI"-xss

[+]: add "isXssFound()" -> so we can check if there was xss-attack v2

[+]: add "isXssFound()" -> so we can check if there was xss-attack