strjust(s) or strjust(s, justify = ``right'') returns
a right-justified character vector. All strings have the same length,
the length of the longest string in s --- but the strings in
s have been trimmed before.
strjust(s, justify = ``left'') does the same, with all strings
left-justified.
strjust(s, justify = ``centered'') returns all string in s
centered. If an odd number of blanks has to be added, one blank more is
added to the left than to the right.