opencats-0.9.6 PHP 7.2 support

Merging develop back to master. Develop has been installed locally fo…

…r UAT (passed) (#527)

@RussH updated version to 0.9.6
@pribeiro42 Update index.php (#498) … a0b3324 
@KPull Fix a syntax error in the Mailer.php file (#511) … fb73517 
@RussH Update composer.json (#525) …