Python: move interpreters

Move Python interpreters (CPython, PyPy) to same folder and share
layout.

pkgs/development/interpreters/python/cpython/docs/2.7-pdf-letter.nix

@@ -0,0 +1,18 @@
+# This file was generated and will be overwritten by ./generate.sh
+
+{ stdenv, fetchurl, lib }:
+
+stdenv.mkDerivation rec {
+  name = "python27-docs-pdf-letter-2.7.3";
+  src = fetchurl {
+    url = http://docs.python.org/ftp/python/doc/2.7.3/python-2.7.3-docs-pdf-letter.tar.bz2;
+    sha256 = "0x41phsdrpivhzkchswsliyx3a10n7gzc9irkrw6rz22j81bfydg";
+  };
+  installPhase = ''
+    mkdir -p $out/share/doc/python27
+    cp -R ./ $out/share/doc/python27/pdf-letter
+  '';
+  meta = {
+    maintainers = [ lib.maintainers.chaoflow ];
+  };
+}