Fix XSS vulnerability in one of the code examples, CVE-2017-11503. The code_generator.phps example did not filter user input prior to output. This file is distributed with a .phps extension, so it it not normally executable unless it is explicitly renamed, so it is safe by default. There was also an undisclosed potential XSS vulnerability in the default exception handler (unused by default). Patches for both issues kindly provided by Patrick Monnerat of the Fedora Project.