Improved the browser build

Made three improvements to the browser build:

1. It now builds _two_ browser bundles, one minified (49kb) and one unminified (129kb)
2. It now builds source maps, which makes debugging in a browser easier
3. `npm start` now runs with `--watch`, so it automatically does _fast_ differential rebuilds when any source files change

Author: JamesMessinger

dist/chai-http.js

@@ -21,10 +21,10 @@
   },
   "scripts": {
     "build": "npm run build:readme && npm run build:js",
-    "prebuild:js": "mkdir -p dist",
-    "build:js": "browserify lib/http.js --outfile dist/chai-http.js --standalone chaiHttp",
+    "prebuild:js": "rm -rf dist",
+    "build:js": "simplifyify lib/http.js --outfile dist/chai-http.js --bundle --minify --debug --standalone chaiHttp",
     "build:readme": "rm -rf README.md && node ./support/readme",
-    "start": "npm run build && http-server -c-1",
+    "start": "npm run build -- --watch & http-server -o -c-1",
     "test": "istanbul cover --report lcovonly _mocha",
     "posttest": "if [ -z \"$COVERALLS_REPO_TOKEN\" ]; then cat coverage/lcov.info | coveralls; fi"
   },
@@ -42,7 +42,7 @@
     "superagent": "1.2.x"
   },
   "devDependencies": {
-    "browserify": "*",
+    "simplifyify": "^2.0.1",
     "chai": "*",
     "coveralls": "^2.11.6",
     "dox": "*",