TODO file---------* replace matrix inversion with resubstitution in HCCL* find general solution for getopt.h availability* detection of NaN while reading from stream, throw at least an error message* matlab export* unsolved problem: how to handle `command line arguments' on source code level* make DDL language a XML derivative (?)* database support (by replacing Read/WriteDDLStream)* graphical user interface (several ideas, but no time :-( )