Move key strings into util.keys so they can be used by other libraries.
Move key strings into util.keys so they can be used by other libraries.

alias-mac/crosstab,tranphuoctien/crosstab,alias-mac/crosstab,tejacques/crosstab,scaryzet/crosstab,tejacques/crosstab,scaryzet/crosstab,tejacques/crosstab,tranphuoctien/crosstab