Replace remaining grunt tasks with npm scripts

.gitignore

@@ -4,5 +4,4 @@ npm*
 test/lib/
 dist/
 openpgp.store/
-doc/
 .nyc_output/

.jsdocrc.js

@@ -1,3 +1,6 @@
 module.exports = {
-    plugins: ['plugins/markdown']
+    plugins: ['plugins/markdown'],
+    markdown: {
+        idInHeadings: true
+    }
 };

.travis.yml

@@ -39,7 +39,7 @@ matrix:
     - node_js: "9"
 
 before_script:
-  - npm install -g grunt-cli codeclimate-test-reporter browserstack-runner
+  - npm install -g codeclimate-test-reporter browserstack-runner
 script:
   - $TRAVIS_BUILD_DIR/travis.sh
 install: npm install

README.md

@@ -563,9 +563,9 @@ To create your own build of the library, just run the following command after cl
 
     npm install && npm test
 
-For debugging browser errors, you can open `test/unittests.html` in a browser or, after running the following command, open [`http://localhost:3000/test/unittests.html`](http://localhost:3000/test/unittests.html):
+For debugging browser errors, you can run `npm start` and open [`http://localhost:8080/test/unittests.html`](http://localhost:8080/test/unittests.html) in a browser, or run the following command:
 
-    grunt browsertest
+    npm run browsertest
 
 ### How do I get involved?