Improve dev workflow: Travis CI, ESLint, PostCSS… (#98)

* Add Autoprefixer
* Add .browserslistrc
* Add ESLint
* Add Travis CI
* Update packages
* Update .stylelintrc

Fix #97

.browserslistrc

@@ -0,0 +1,4 @@
+> 0.25%
+not dead
+IE >= 10
+iOS >= 7

.eslintrc

@@ -0,0 +1,7 @@
+{
+  "extends": "airbnb-base/legacy",
+  "rules": {
+    "indent": [2, "tab"],
+    "no-tabs": 0
+  }
+}

.postcssrc

@@ -0,0 +1,7 @@
+{
+  "plugins": {
+    "autoprefixer": {
+      cascade: false
+    }
+  }
+}

.stylelintrc

@@ -119,8 +119,7 @@
       "flex-flow",
       "flex-shrink",
       "flex-grow",
-      "flex-order",
-      "flex-pack",
+      "flex-wrap",
       "align-content",
       "align-items",
       "align-self",
@@ -310,7 +309,10 @@
       "animation-iteration-count",
       "animation-direction",
       "animation-fill-mode",
+      "quotes",
+      "will-change",
       "fill",
+      "fill-rule",
       "stroke"
     ]
   }

.travis.yml

@@ -0,0 +1,8 @@
+language: node_js
+node_js:
+  - "8"
+
+sudo: false
+
+script:
+  - npm run lint

package.json

@@ -5,13 +5,27 @@
   "license": "GPL-2.0",
   "dependencies": {},
   "devDependencies": {
-    "stylelint": "^9.2.0",
-    "stylelint-order": "^0.8.1"
+    "autoprefixer": "^9.2.1",
+    "eclint": "^2.8.0",
+    "eslint": "^5.7.0",
+    "eslint-config-airbnb-base": "^13.1.0",
+    "eslint-plugin-import": "^2.14.0",
+    "eslint-plugin-node": "^7.0.1",
+    "postcss-cli": "^6.0.1",
+    "stylelint": "^9.6.0",
+    "stylelint-order": "^1.0.0"
   },
   "scripts": {
     "lint:css": "stylelint static/css/*.css",
-    "lint": "npm run lint:css",
-    "test": "echo \"Error: no test specified\" && exit 1"
+    "lint:js": "eslint static/js/*.js",
+    "lint:editorconfig": "eclint check '**/*.{html,css,js,json,md,toml,yaml,yml}'",
+    "lint": "npm run lint:css && npm run lint:js && npm run lint:editorconfig",
+    "fix:prefixes": "postcss -r static/css/*.css",
+    "fix:css": "stylelint static/css/*.css --fix",
+    "fix:js": "eslint static/js/*.js --fix",
+    "fix:editorconfig": "eclint fix '**/*.{html,css,js,json,md,toml,yaml,yml}'",
+    "fix": "npm run fix:prefixes && npm run fix:css && npm run fix:js && npm run fix:editorconfig",
+    "test": "npm run lint"
   },
   "repository": {
     "type": "git",