Summary of important user-visible changes for dataframe 1.2.0:
-------------------------------------------------------------------

 ** dataframe 1.2.0 is a major update. Most of the mapping functions are
    now supported: abs, acosh, acos, all, and, angle, any, arg, ... They
    are simple proxies to the corresponding Octave functions.
    -- The display function now supports 3.8, 4.0, 4.2, and upcoming 4.4
       Octave major release.
    -- if some specific output format is requested, it must come first,
       e.g. x.dataframe([1:10]) instead of x([1:10].dataframe
    -- a longstanding bug on default separator was corrected. If more than
       one are used, they must be grouped into a cellstr instead of a str
    -- a dataframe may now contain 'pages' corresponding to a third
       dimension. The inner mechanism uses a "copy-on-write" scheme
       and avoid duplicating content repeated over many pages.

Summary of important user-visible changes for dataframe 1.1:
-------------------------------------------------------------------

 ** dataframe 1.1.0 is a major update. As it introduces new functions, if 
    dataframe-1.0.1 was previously loaded, Octave has to be restarted.
    Significants changes:
    - the structure of "row empty", i.e. dataframes with [0, n] size,
      is fully displayed
    - the "_src" metadata is now correctly set
    - new function: nth_element, make it compatible with median. Note 
      that only row-median and page median are implemented, using directly
      the underlying data structures
    - new function; numel. Only the one argument form is supported.
    - bsxfun now better handles array as first arguement
    - vector vs matrix plot are now supported, provided both data set possess
      the same colum length. 

