- Renamed old Vcopy.py to OldVcopy.py, some cosmetic changes to it (is
  it still needed?)
- Added new Vcopy.py which does everything that Vtime.py does but also
  format conversions, image scaling, and packfactors.
- VFile: make packfactor always a tuple; introduce set and get methods
  for pf, format, and calculate some derived values.
- Added new module GET.py to std library, use it instead of defining
  DM* in VFile.
- Get rid of C programs (new Python programs can do all that they do
  and they probably don't understand the current file format anyway).