imadoc2struct

'imadoc2struct': reads the xml file for image documentation 

function [s,errormsg]=imadoc2struct(ImaDoc) 
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 OUTPUT:
 s: structure representing ImaDoc
   s.Heading: information about the data hierarchical structure
   s.Time: matrix of times
   s.TimeUnit
  s.GeometryCalib: substructure containing the parameters for geometric calibration
 errormsg: error message

 INPUT:
 ImaDoc: full name of the xml input file with head key ImaDoc
function [s,error,Heading,nom_type_ima,ext_ima,abs_time,TimeUnit,mode,NbSlice]=imadoc2struct(ImaDoc)