reverted my changes for hdur_tiny(), which did not fix the bug when FORCE_SOLUTION is used
cleaned useless white spaces
temporarily patched Matthieu's model_SEP() source code, which had broken the package
fixed the "hdur_tiny" bug detected by Alexis Bottero in the case of FORCE_SOURCESOLUTION with a Dirac source time function (hdur_tiny was not sent as a subroutine argument)