FEAT: added missing mezz type testing functions: file? and issue?.
FEAT: added missing mezz type testing functions: file? and issue?.

iArnold/red,red-eco/red,iArnold/red,rheber/red,NikolayShubenkovProgSchool/red,NikolayShubenkovProgSchool/red,red-eco/red,rheber/red,vehar/red,vehar/red