Miscellaneous-initConstLatex: Initializateurs for the constLatex function
In bozenne/MRIaggr: Management, Display, and Processing of Medical Imaging Data

Initialize arguments of the constLatex function. For internal use.

initDirPat_constLatex(directory, param, identifier, verbose)

initSection_constLatex(directory.plot, names_dirs, param, subsection, label)

initPlot_constLatex(directory, names_dirs, directory.plot, identifier, 
         tabular, plotPerPage)

`directory`	the path to the root directory. This directory should contains subsdirectories themself containing the image files. character.
`directory.plot`	the paths to the subdirectory(ies) containing the image files. character or character vector.
`names_dirs`	the names of the subdirectory(ies). character or character vector.
`identifier`	the identifiers of the patients for which the graphics should be displayed. character vector or `NULL` leading to use all patients.
`param`	the names of directories containing the images. character vector or `NULL` leading to use all directories.
`tabular`	a list of data.frame to display in the table format. list of data.frame or `NULL` if there is no table to display.
`subsection`	the names of subsections for the latex document. character vector or `NULL` leading to use `param` for naming the subsections.
`label`	the legend that will be displayed under each figure of a given parameter. character vector or `NULL` leading to use `param` for the legend.
`verbose`	should the execution of the function be traced ? logical.
`plotPerPage`	the number of image that should be displayed on the same page. strictly positive interger.