Added visual regression test

package.json

@@ -47,11 +47,13 @@
 	},
 	"devDependencies": {
 		"autoprefixer": "^6.3.6",
+		"backstopjs": "^1.3.5",
 		"browser-sync": "^2.13.0",
 		"node-sass": "^3.7.0",
 		"npm-run-all": "^2.1.1",
 		"onchange": "^2.4.0",
-		"postcss-cli": "^2.5.2"
+		"postcss-cli": "^2.5.2",
+		"slimerjs": "^0.906.2"
 	},
 	"engines": {
 		"node": "^6.0.0"
@@ -63,6 +65,7 @@
 		"build": "npm-run-all sass autoprefixer banner",
 		"watch": "onchange src -- npm run build",
 		"serve": "browser-sync start -s test --ss dist -f dist",
-		"start": "npm-run-all -p watch serve"
+		"start": "npm-run-all -p watch serve",
+		"test": "cd node_modules/backstopjs && npm run test -- --configPath=../../test/visual/backstop.config.js && cd ../../"
 	}
 }

test/visual/backstop.config.js

@@ -0,0 +1,33 @@
+module.exports = {
+	viewports: [
+		{ name: 'phone_v', width: 320, height: 480 },
+		{ name: 'phone_h', width: 480, height: 320 },
+		{ name: 'tablet_v', width: 768, height: 1024 },
+		{ name: 'tablet_h', width: 1024, height: 768 },
+		{ name: 'laptop', width: 1280, height: 800 },
+		{ name: 'desktop', width: 1920, height: 1080 }
+	],
+	scenarios: [{
+		label: 'Milligram | A minimalist CSS framework.',
+		url: 'http://localhost:3000',
+		hideSelectors: [],
+		removeSelectors: ['.__bs_notify__'],
+		selectors: ['body'],
+		readyEvent: null,
+		delay: 500,
+		misMatchThreshold: 0.1,
+		onBeforeScript: 'onBefore.js',
+		onReadyScript: 'onReady.js'
+	}],
+	paths: {
+		bitmaps_reference: '../../test/visual/reference',
+		bitmaps_test: '.tmp',
+		casper_scripts: '../../test/visual/fixtures',
+		compare_data: '.tmp/compare.json'
+	},
+	engine: 'slimerjs',
+	report: ['browser'],
+	casperFlags: [],
+	debug: false,
+	port: 3002
+}

test/visual/fixtures/onBefore.js

@@ -0,0 +1,4 @@
+module.exports = function(casper, scenario, vp) {
+	casper.echo('onBeforeEach.js', 'INFO');
+	casper.wait(50);
+};

test/visual/fixtures/onReady.js

@@ -0,0 +1,4 @@
+module.exports = function(casper, scenario, vp) {
+	casper.echo('onReady.js', 'INFO');
+	casper.wait(50);
+};