don't hook on postinstall, current dev cycle uses (abuses) npm i to build

so no point making it take longer than it has to for the devs only testing
webapp

build:electron - hook npm run install:electron
install:electron - run npm i for the electron deps
electron - start the app locally for testing

add to README

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

README.md

@@ -135,6 +135,7 @@ To run as a desktop app:
 
    ```
    npm install electron
+   npm run install:electron
    node_modules/.bin/electron .
    ```
 

package.json

@@ -32,11 +32,12 @@
     "build:compile": "babel --source-maps -d lib src",
     "build:bundle": "NODE_ENV=production webpack -p --progress",
     "build:bundle:dev": "webpack --optimize-occurence-order --progress",
-    "build:electron": "npm run clean && npm run build && build -wml --ia32 --x64",
+    "build:electron": "npm run clean && npm run build && npm run install:electron && build -wml --ia32 --x64",
     "build": "node scripts/babelcheck.js && npm run build:res && npm run build:bundle",
     "build:dev": "node scripts/babelcheck.js && npm run build:res && npm run build:bundle:dev",
     "dist": "scripts/package.sh",
-    "postinstall": "cd electron && npm i",
+    "install:electron": "cd electron && npm i",
+    "electron": "npm run install:electron && electron .",
     "start:res": "node scripts/copy-res.js -w",
     "start:js": "webpack-dev-server --output-filename=bundles/_dev_/[name].js --output-chunk-file=bundles/_dev_/[name].js -w --progress",
     "start:js:prod": "NODE_ENV=production webpack-dev-server -w --progress",