% Display a summary of an sqw object or file containing sqw information.
% 
%   >> head(w)              % Summary for object (or array of objects)
%   >> head(sqw,filename)   % Summary for named file (or array of names)
%
% To return header information in a structure, without displaying to screen:
%
%   >> h=head(...)          % Fetch principal header information
%   >> h=head(...,'-full')  % Fetch full header information
%
%
% The facility to get head information from file(s) is included for completeness, but
% more usually you would use the function:
%   >> head_horace(filename)
%   >> h=head_horace(filename)
%   >> h=head_horace(filename,'-full')
%
%
% Input:
% -----
%   w           sqw object or array of sqw objects
%       *OR*
%   sqw         Dummy sqw object to enforce the execution of this method.
%               Can simply create a dummy object with a call to sqw:
%                   e.g. >> w = head(sqw,'c:\temp\my_file.sqw')
%
%   file        File name, or cell array of file names. In latter case, displays
%               summary for each sqw object
%
% Optional keyword:
%   '-full'     Keyword option; if present, then returns all header and the
%              detecetor information. In fact, it returns the full data structure
%              except for the signal, error and pixel arrays.
%
% Output (optional):
% ------------------
%   h           Structure with header information, or cell array of structures if
%               given a cell array of file names.
%%   Overloaded methods:
%      sqw/head
%      sqw/head
%      d4d/head
%      d3d/head
%      d2d/head
%      d1d/head
%      d0d/head
%