Update tooling (#99)

- Update browserify, serve, and tape to the latest versions
- update the example script to reflect serve's new CLI options
- Remove the uneeded dependency on opn-cli
- Force Travis to use NPM 5.x
- Remove bower.json

.travis.yml

@@ -2,3 +2,6 @@ language: "node_js"
 node_js:
   - "6"
   - "8"
+# Force Travis to use npm v5
+# https://github.com/travis-ci/travis-ci/issues/4653#issuecomment-194051953
+before_install: if [[ `npm -v` != 5* ]]; then npm i -g npm@5; fi