- streamline evt-handling in example.js

- migrate browser-testing from electron to headless-chromium
- rename rm -fr to rm -rf
- revamp function local.ajaxProgressUpdate with window.domOnEventAjaxProgressUpdate
- istanbul - switch parser from esprima to acorn v6.3.0

.gitignore

@@ -6,7 +6,6 @@
 .*
 core
 data
-electron-lite
 example.js
 external
 package-lock.json

.travis.yml

@@ -1,7 +1,6 @@
+addons:
+    chrome: stable
 before_install:
-    # init xvfb
-    # http://docs.travis-ci.com/user/gui-and-headless-browsers/
-    - export DISPLAY=:99.0 && sh -e /etc/init.d/xvfb start
     # override $NODE_VERSION
     - CI_COMMIT_MESSAGE="$(git log -1 --pretty=%s)" && if (printf "$CI_COMMIT_MESSAGE" | grep -qE "\bNODE_VERSION="); then nvm install "$(printf "$CI_COMMIT_MESSAGE" | sed -e "s/.*\bNODE_VERSION=//" -e "s/ .*//")" && node --version && npm --version; fi
 branches:
@@ -16,6 +15,8 @@ branches:
     - /^task$/
 cache:
     npm: false
+dist:
+    xenial
 env:
     global:
     # this value is auto-created by shTravisCryptoAesEncryptYml
@@ -29,6 +30,7 @@ script:
     - npm run build-ci
 services:
     - docker
+    - xvfb
 # http://docs.travis-ci.com/user/workers/container-based-infrastructure
 sudo:
     false