[wip] Add linting and make pass

Add linting according to the eslint kartotherian rules.
Only test node version 6. Version 4 is fairly old, and does not
support the linting rules (mainly the trailing comma pieces)
and Mapnik only supports up to node 6.9.4 for now.

.eslintrc.js

@@ -0,0 +1,21 @@
+module.exports = {
+  extends: 'kartotherian',
+  env: {
+    node: true,
+    es6: true,
+    browser: false,
+  },
+  rules: {
+    'comma-dangle': [
+      'error',
+      {
+        arrays: 'always-multiline',
+        objects: 'always-multiline',
+        imports: 'always-multiline',
+        exports: 'always-multiline',
+        // Dangling commas are unsupported in node
+        functions: 'never',
+      },
+    ],
+  },
+};

.travis.yml

@@ -3,8 +3,8 @@ language: node_js
 sudo: false
 
 node_js:
-  - "0.10"
-  - "0.12"
-  - "4"
   - "6"
-  - "node"
+
+before_install:
+  - sudo apt-get -qq update
+  - sudo apt-get install -y libgif-dev

Gruntfile.js

@@ -0,0 +1,32 @@
+/* eslint-env node */
+module.exports = function Gruntfile(grunt) {
+  grunt.loadNpmTasks('grunt-contrib-watch');
+  grunt.loadNpmTasks('grunt-eslint');
+  grunt.loadNpmTasks('grunt-mocha-test');
+
+  grunt.initConfig({
+    eslint: {
+      code: {
+        src: [
+          '**/*.js',
+          '!node_modules/**',
+          '!vendor/**',
+          '!lib/**',
+          '!coverage/**',
+        ],
+      },
+    },
+    mochaTest: {
+      test: {
+        options: {
+          reporter: 'spec',
+        },
+        src: ['test/**/*.js'],
+      },
+    },
+  });
+
+  grunt.registerTask('lint', 'eslint');
+  grunt.registerTask('test', ['lint', 'mochaTest']);
+  grunt.registerTask('default', 'test');
+};