Escape commas in native escapeClassName and nameClass functions

src/util/escapeClassName.js

@@ -1,8 +1,12 @@
 import parser from 'postcss-selector-parser'
 import get from 'lodash/get'
 
+function escapeCommas(className) {
+  return className.replace(/\\,/g, '\\2c ')
+}
+
 export default function escapeClassName(className) {
   const node = parser.className()
   node.value = className
-  return get(node, 'raws.value', node.value)
+  return escapeCommas(get(node, 'raws.value', node.value))
 }

src/util/nameClass.js

@@ -1,7 +1,11 @@
 import escapeClassName from './escapeClassName'
 
+function escapeCommas(className) {
+  return className.replace(/\\,/g, '\\2c ')
+}
+
 function asClass(name) {
-  return `.${escapeClassName(name)}`
+  return escapeCommas(`.${escapeClassName(name)}`)
 }
 
 export default function nameClass(classPrefix, key) {