mergecellkey: Merge cell by key

function cellB = mergecellskey(varargin)
% PURPOSE: merge cells
% -----------------------------------------------------------------------------
% SYNTAX:
% (1) C = mergecellskey(A,B,{'key1','key2'});
% (2) C = mergecellskey(A1,A2,A3, {'key1'});
% -----------------------------------------------------------------------------
% OUTPUT:
% (1) A new cell contain all columns of the cells
% -----------------------------------------------------------------------
% INPUT:
% (1) cells: NxM --->several cell containing M columns. Each cell
% should contains a colomn with 'key' on the headline
% (2) keys: 1xM ---> a cell containing the keys, it should string cell.
% NB: no string can be include in the file.

% -----------------------------------------------------------------------
% LIBRARY: showcell
% -----------------------------------------------------------------------
% SEE ALSO: join
% -----------------------------------------------------------------------
% REFERENCE: join, eval
% -----------------------------------------------------------------------
% written by:
% Lin Renwen
% <linrenwen@gmail.com>

% Version 1.0 [2012-11-9 11:55:15]

%=============================================
% EXAMPLE:
% A = {'Year', 1979, 1980 1981 1982 ; 'a' ,1,5,2, 4; 'c', '4', '3', '4','9yy'}';
% B = {'Year', 1980 1981 1982 1983; 'a' ,NaN,2,4,7 ; 'c', '3', '4', '677','pp'}';
% C = mergecellskey(A,B,{'Year'});
% showcell(C);
% % END OF EXAMPLE
%=============================================