Add GNU Public Licence v3.0 declarations for .cpp, .cxx, .h, .C files.

Licence declaration is added to most .cpp, .cxx, .h, and .C files. Skips declaration on files detected with previous authorship or copyright. Inserts following four-line header schema following doxygen rules for files

/** @file "basename.cxx"

• @copyright Copyright (C) YEAR-LAST_EDITED_YEAR Institute, City
  
• @license SPDX-License-Identifier: GPL-3.0-only
  
• @authors Contributer_1, Contributor_2 [orginator], Contributer_3 **/
  

The author information and details are pulled from the CBMCDB. Contributers of over 10% of the lines are declared in order of their contribution as authors. Original commiter has [originator] placed beside name. Copyright is declared for the institute of the original commiter into the SVN or GIT repositories. Single Institutes have full name with City, double Affiliations are abbreviated into their short-form.