Updated authorship, messages, CHANGELOG and README from cde_weaklynl.red
Updated one example of calculation of Schouten bracket for a Hamiltonian operator for the mKdV equation
Time-stamp of the README.txt file updated
Fixed a bug in cde_weaklynl.red and added example programs for this library in the folder examples_wnlop.
Shortened the list of arguments in a procedure in order to comply with a restriction of PSL on the number of arguments.
Bug fixing: now the example h_nb1.red in examples_book works properly, and a consistency check in schouten_bracket_wnl behaves in the right way.
This is a major update of the package CDE to version 3.0.
The CDE section of the manual has been updated with comments and new references