feat: better kebab case conversion

Also added test

addon/__tests__/prefixer.test.js

@@ -0,0 +1,42 @@
+/* eslint-disable */
+'use strict';
+
+var env = require('./env');
+var create = require('../../index').create;
+var addonPrefixer = require('../../addon/prefixer').addon;
+
+function createNano (config) {
+	var nano = create(config);
+
+	addonPrefixer(nano);
+
+	return nano;
+};
+
+describe('prefixer', function () {
+	it('installs without crashing', function () {
+		var nano = createNano();
+		expect(nano).toBeDefined();
+	});
+
+	it('handles "user-select" correctly', function() {
+		var nano = createNano();
+
+		nano.putRaw = jest.fn();
+
+		nano.put('.one', {
+			'user-select': 'none'
+		});
+
+		var result = nano.putRaw.mock.calls[0][0].replace(/ +(?= )/g,'');
+		[
+			'-ms-user-select',
+			'-moz-user-select',
+			'-webkit-user-select',
+			'user-select'
+		].forEach(function(key) {
+			expect(result.includes(key)).toBe(true);
+		});
+
+	});
+});

addon/prefixer.js

@@ -24,6 +24,9 @@ exports.addon = function (renderer) {
 
         for (var propPrefixed in obj) {
             value = obj[propPrefixed];
+            if (propPrefixed.slice(0, 2) === 'ms') {
+                propPrefixed = 'M' + propPrefixed.slice(1);
+            }
             propPrefixed = renderer.kebab(propPrefixed);
 
             if (value instanceof Array) {