pycoin: expose cli via top-level entry
pycoin: expose cli via top-level entry

pycoin is a python crypto currency library,
which was added to nixpkgs python modules in
commit 2b11dcd789f60961473830b7202f9b44810a455c .
However, it also brings some command line tools,
which may be accessed by building it as python application.
This commit adds the corresponding entry to `all-packages.nix`.

NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs