printSize() fixes
printSize() fixes

Fix a 32-bit overflow that resulted in negative numbers being printed;
use fmt() instead of boost::format(); change -H to -h for consistency
with 'ls' and 'du'; make the columns narrower (since they can't be
bigger than 1024.0).

vcunat/nix,NixOS/nix,pikajude/nix,NixOS/nix,layus/nix,rycee/nix,layus/nix,NixOS/nix,rycee/nix,rycee/nix,dtzWill/nix,zimbatm/nix,zimbatm/nix,vcunat/nix,ehmry/nix,layus/nix,dtzWill/nix,NixOS/nix,NixOS/nix,dtzWill/nix,ehmry/nix,ehmry/nix,dtzWill/nix,ehmry/nix,zimbatm/nix,zimbatm/nix,pikajude/nix,layus/nix,ehmry/nix,vcunat/nix,vcunat/nix,ehmry/nix,rycee/nix,dtzWill/nix,layus/nix,rycee/nix,pikajude/nix