added an output() function to move the I/O out of the algorithm

Viewer.py in turn requires changes to VFile.py (unfortunately that file
is now a complete mess...).

Added optional read-ahead thread.
Changed mouse interface.

Cleverer skipping of frames.

saves the cache.
Added getinfo() to VoutFile.
Fixed writing of 'grey' file header.
Added quiet parameter.
Adapted to new syntax.

  argument to malloc() (size_t or unsigned int)

* listobject.c: check for overflow of the size of the object,
  so things like range(0x7fffffff) will raise MemoryError instead
  of calling malloc() with -4 (and then crashing -- malloc's fault)

break window positions in .Xdefaults)

true, not false!!!