Uri: add test for IPv6 address in HTTP_HOST
Uri: add test for IPv6 address in HTTP_HOST

HTTP_HOST can contain IPv6 addresses of the form [2001:db8::1]
(example). the current Uri::createFromEnvironment() implementation
splits such hosts at the first colon, yielding "[2001" instead of
the full IPv6 address. additionally, IPv6 ports are given after the
brackets (eg. [2001:db8::1]:80).

refs #1325

mnapoli/Slim,RealSelf/Slim,feryardiant/slim,JoeBengalen/Slim,iinux/Slim,AndrewCarterUK/Slim,foxyantho/Slim,Sam-Burns/Slim,iinux/Slim,juliangut/Slim,slimphp/Slim,dopesong/Slim,iinux/Slim,designermonkey/Slim,akrabat/Slim