Idepth and other issues

[Tim Bedding]

The file main.c has a variable
  int Idepth;
and I cannot see what this means.

I checked the README but did not find
anything on it.

There seems to be a calculation
Idepth/DEPTH which always returns
an integer. Is this the number of
ply? Could the code be simplified
to avoid this calculation?

Also, it would be nice for the
README to cover the output format
of the principal variation.

I see 1+ 2& 2. but do not know
what they mean.

Regards
Tim