feat: Update API

BREAKING CHANGE: 

Each icon in the `feather.icons` object is now an `Icon` object with a `name`, `contents`, `tags` and `attrs` property.
```js
/* BEFORE */
feather.icons.x
// '<line ... /><line ... />'

/* AFTER */
feather.icons.x
// {
//    name: 'x',
//    contents: '<line ... /><line ... />`,
//    tags: ['cancel', 'close', 'delete', 'remove'],
//    attrs: {
//      class: 'feather feather-x',
//      xmlns: 'http://www.w3.org/2000/svg',
//      width: 24,
//      height: 24,
//      viewBox: '0 0 24 24',
//      fill: 'none',
//      stroke: 'currentColor',
//      'stroke-width': 2,
//      'stroke-linecap': 'round',
//      'stroke-linejoin': 'round',
//    }
// }
```

`feather.toSvg()` has been deprecated in favor of `feather.icons[name].toSvg()`:
```js
/* BEFORE */
feather.toSvg('x')

/* AFTER */
feather.icons.x.toSvg()
```

`feather.replace()` now copies all attributes on the placeholder element (i.e. `<i>`) to the `<svg>` tag instead of just `class` and `id`:

```html
<i data-feather="circle" id="my-circle" class="foo bar" stroke-width="1"></i>
<!--
<i> will be replaced with:
<svg id="my-circle" class="feather feather-circle foo bar" xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1" stroke-linecap="round" stroke-linejoin="round"><circle cx="12" cy="12" r="10"></circle></svg>
-->
```

package.json

@@ -7,30 +7,36 @@
     "dist"
   ],
   "scripts": {
-    "all": "make",
-    "lint": "make lint",
-    "test": "make test",
-    "build": "make build",
+    "start": "npm-run-all --sequential build lint test",
+    "build": "./bin/build.sh",
+    "lint": "eslint .",
+    "test": "jest",
     "commitmsg": "validate-commit-msg",
     "cm": "git-cz",
     "semantic-release": "semantic-release pre && npm publish && semantic-release post"
   },
+  "dependencies": {
+    "classnames": "^2.2.5"
+  },
   "devDependencies": {
     "babel-cli": "^6.24.1",
     "babel-loader": "^7.1.1",
+    "babel-plugin-transform-object-rest-spread": "^6.26.0",
     "babel-preset-es2015": "^6.24.1",
     "babel-register": "^6.24.1",
     "cheerio": "^1.0.0-rc.2",
     "commitizen": "^2.9.6",
     "core-js": "^2.4.1",
-    "cz-conventional-changelog": "^2.0.0",
+    "cz-conventional-changelog": "^2.1.0",
     "eslint": "^4.0.0",
     "eslint-config-airbnb-base": "^11.2.0",
     "eslint-plugin-import": "^2.5.0",
     "husky": "^0.13.4",
     "jest": "^21.2.1",
+    "npm-run-all": "^4.1.2",
     "parse5": "^3.0.2",
     "prettier": "^1.8.2",
+    "rimraf": "^2.6.2",
     "rsvp": "^3.6.0",
     "semantic-release": "^6.3.6",
     "svgo": "^0.7.2",