ROBUSTNESS: Add explicit 'stringsAsFactors' arguments [data.frame]

[HenrikBengtsson]

$ for pkg in $pkgs; do echo "$pkg:"; (cd "$pkg"; grep -E "^[ \t]*[^#].*data[.]frame" -- */*.R | grep -vF stringsAsFactors;); echo; read -r -p "Press ENTER to continue ..."; done
affxparser:
R/readCcg.R:  class(table) <- "data.frame";
R/readCdfDataFrame.R:    attr(df, "class") <- "data.frame";
R/updateCel.R:    intensities <- as.data.frame(intensities);
R/updateCel.R:  if (is.list(intensities) || is.data.frame(intensities)) {