Update CI build configurations

The build configuration for "Circle CI" (1) have been updated to the new
API version 2.0 (2). Both Circle CI and "Travis CI" (3) have been changed
to use "npm" (4) instead of "yarn" (5).

References:

  (1) https://circleci.com
  (2) https://circleci.com/docs/2.0
  (3) https://travis-ci.org
  (4) https://www.npmjs.com
  (5) https://yarnpkg.com

GH-20

.circleci/config.yml

@@ -0,0 +1,26 @@
+# Copyright (c) 2017-present Arctic Ice Studio <[email protected]>
+# Copyright (c) 2017-present Sven Greb <[email protected]>
+
+# Project:    Nord Hyper
+# Repository: https://github.com/arcticicestudio/nord-hyper
+# License:    MIT
+# References:
+#   https://circleci.com/docs/2.0
+#   https://circleci.com/docs/2.0/circleci-images/#nodejs
+
+version: 2
+jobs:
+  build:
+    docker:
+      - image: circleci/node:8.7
+    steps:
+      - checkout
+      - run:
+          name: install-global-gulp-cli
+          command: sudo npm install -g gulp-cli
+      - run:
+          name: npm-install
+          command: npm install
+      - run:
+          name: lint
+          command: gulp --harmony lint

.npmrc

@@ -0,0 +1,2 @@
+package-lock=false
+save-exact=true

.travis.yml

@@ -8,11 +8,18 @@
 #   https://docs.travis-ci.com/user/languages/javascript-with-nodejs
 
 language: node_js
+dist: trusty
+sudo: false
 node_js:
   - "6"
-  - "4"
-cache: yarn
+  - "8"
+os:
+  - linux
+  - osx
+before_install:
+  - rm -rf ./node_modules
 before_script:
-  - yarn global add gulp
-  - yarn install
+  - npm install -g gulp-cli
+  - npm install gulp
+  - npm install
 script: gulp --harmony lint