node-packages.nix: Convert to new npm2nix style

Starting with 1.0.0 (which is not released at the time of this commit
but will be before it is pushed), npm2nix takes a JSON file with a list
of names (and optionally version ranges) and generates a data-only (no
functions, no rec, no let, etc.) nix expression representing the
packages with those names and their dependencies.

node-packages.nix now builds its package list from that generated
expression. If a package needs native dependencies as build inputs, they
can be added to the nativeDeps attribute set. If a package cannot be
generated by npm2nix for some reason, it can be added manually to the
set.

I tried to capture the packages represented by the previous
node-packages.nix in the new node-packages.json, but I almost certainly
missed some that will have to be added manually.

Signed-off-by: Shea Levy <shea@shealevy.com>

pkgs/top-level/node-packages.json

@@ -0,0 +1,34 @@
+[
+  { "name": "async" }
+, { "name": "assert" }
+, { "name": "mocha" }
+, { "name": "jayschema" }
+, { "name": "underscore" }
+, { "name": "extend" }
+, { "name": "express" }
+, { "name": "s3http" }
+, { "name": "aws-sdk" }
+, { "name": "nijs" }
+, { "name": "amdefine" }
+, { "name": "smartdc" }
+, { "name": "optparse" }
+, { "name": "jsontool" }
+, { "name": "swig" }
+, { "name": "coffee-script" }
+, { "name": "escape-html" }
+, { "name": "buffertools" }
+, { "name": "wu" }
+, { "name": "source-map" }
+, { "name": "knox" }
+, { "name": "node-expat" }
+, { "name": "optimist" }
+, { "name": "temp" }
+, { "name": "faye-websocket" }
+, { "name": "node-uuid" }
+, { "name": "rbytes" }
+, { "name": "sockjs" }
+, { "name": "backbone" }
+, { "name": "browserchannel" }
+, { "name": "node-gyp" }
+, { "name": "semver" }
+]