add script to deploy gh-pages branch (video-dev#1875)

* deploy demo and docs to gh-pages

* also add readme to root

* move api docs to 'api-docs'

.esdoc.json

@@ -1,5 +1,5 @@
 {
   "source": "./src",
-  "destination": "./docs/html",
+  "destination": "./api-docs",
   "plugins": [{"name": "esdoc-standard-plugin"}]
 }

.gitignore

@@ -16,3 +16,5 @@ coverage/
 
 # Build
 /dist
+/gh-pages
+/api-docs

.travis.yml

@@ -36,6 +36,18 @@ jobs:
         skip_cleanup: true
         on:
           tags: true
+    - stage: buildAndTest
+      if: branch = master AND type != pull_request
+      env: TRAVIS_MODE=gh-pages
+      deploy:
+        provider: pages
+        github_token:
+          secure: "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"
+        skip_cleanup: true
+        keep_history: false
+        local_dir: gh-pages
+        on:
+          tags: true
     # publish canary package if on master
     - stage: releaseCanary
       if: branch = master AND type != pull_request