Version 0.55 (2014-03-09)

o plot.ca() and plot.mjca() now provide sensible default xlab and ylab

o mjca() now accepts a table object as input, using internal expand.dft

o ca() has been made generic, accepting input in the form of matrices, data frames 
  (coerced to frequency tables), objects of class "xtabs" or "table" and one-sided
  formulae of the form ~ F1 + F2, where F1 and F2 are factors.

Version 0.54 (2014-01-05)

o Added xlab=, ylab= and lines= arguments to plot.ca().  The function now returns an
  invisible result containing the row and column coordinates calculated internally for
  the plot, for use in additional plot annotation.

o Added xlab=, ylab= arguments to plot.mjca().  The function now returns an
  invisible result containing the row and column coordinates calculated internally for
  the plot, for use in additional plot annotation.
 
o For plot.ca(), the defaults for xlab= and ylab= were changed from "" to "_auto_",
  meaning that the axis labels are auto-generated to be of the form "Dimension X (xx.xx%)"
  in conformance with other dimension reduction plots.

o Added col.lab argument to plot.ca(), to provide colors for the point labels, similar to
  col for points.
