#1678 Output of useful numbers to StdErr via 7z

[RFlash]

Hello! I've been making a non-console script for a long time, where it was necessary to check some data before unpacking/updating, but I had to do this through parsing after 7z l -slt and specifying the correct encoding, but this is slower and not always reliable, because it doesn't work with all archive types.

So, what numbers (for a very long time) did I want to see in the stderr stream after executing 7z l -bso0 -bsp0:

-bse3 [{wildcard}] — number of items in the archive root
-bse4 [{wildcard}] — number of folders in the archive root
-bse5 [{wildcard}] — number of files in the archive root
-bse6 [{wildcard}] — size of the contents at the archive root
-bse7 [{wildcard}] — size of folders in the archive root in bytes
-bse8 [{wildcard}] — size of files in the archive root in bytes

I would be very grateful for such an implementation!

[RFlash]

Igor, what do you think? Can you do that? For now, you can start with the total number (-bse3) and size (-bse6) without a mask, and then add something else.