upload data from digiflow .dfc format into matlab

Converts data written in digiflow .dfc format to be able to be used in matlab.

% function to open a dfc file saved by the write_file function in digiflow
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% The arrays are changed from base 0 to base 1.
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% Inputs:
% filename: the dfc file to be opened
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% Outputs:
% variables_structure: an object containing the variables as fields
% saved data: none
% plots:none
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