make npm scripts work under Windows

Yes, make-dist-dir is a horrible hack around the missing -p option of mkdir.

package.json

@@ -25,11 +25,12 @@
     "async"
   ],
   "scripts": {
-    "build-dist": "mkdir -p dist && rollup src/main.js | babel -m umd --module-id creed -o dist/creed.js --loose es6.classes",
-    "build": "npm run build-dist && uglifyjs -c 'warnings=false' -m -o dist/creed.min.js -- dist/creed.js",
+    "make-dist-dir": "if not exist dist (mkdir dist)",
+    "build-dist": "npm run make-dist-dir && rollup src/main.js | babel -m umd --module-id creed -o dist/creed.js --loose es6.classes",
+    "build": "npm run build-dist && uglifyjs -m -o dist/creed.min.js -- dist/creed.js",
     "preversion": "npm run build",
     "test-aplus": "promises-aplus-tests test/aplus.js --reporter dot",
-    "test-main": "istanbul cover --root src _mocha -- --reporter dot",
+    "test-main": "istanbul cover --root src node_modules/mocha/bin/_mocha -- --reporter dot",
     "check-coverage": "istanbul check-coverage --statements 100 --branches 100 --lines 100 --functions 100 coverage/coverage*.json",
     "lint": "jsinspect src && eslint src",
     "test": "npm run lint && npm run build && npm run test-main && npm run check-coverage && npm run test-aplus"