Bug 448500 - Add "\" prefix for global function call inside namespace

Change-Id: I7a3c2fedec2240e5d734534f977bc2a65c39f16a
Signed-off-by: Michal Niewrzal <michal.n@zend.com>
No bug - Formatter option group label changed from "Phpdoc" into
"PHPDoc"

Change-Id: I784d1119a7f3f62c4dcdb95bf0b773fcf5ecac40
Signed-off-by: Michal Niewrzal <michal.n@zend.com>