checkpoint commit of initial attempt at rendering text in the offline comp using CoreText, currently non functional
flip the Y coordinate used with AVOfflineComposition, users will expect 0,0 to be in the upper left corner, slight incompatibility but not serious
prepare AVOfflineComposition for arc upgrade by use autoreleasepool keywork and making autorelease calls conditional
checkpoint commit after moving attr str render logic into MutableAttrString.m, attempt to address memory leak but it turns out this is in CoreText and cannot be fixed externally
enable clip specific font settings so that comp settings become the default when clip font settings are not indicated, add test case