chore: update eslint config, and added lint task to makefile

Author: danieljuhl

.eslintrc

@@ -6,8 +6,12 @@
     "node": true,
     "mocha": true
   },
-  "ecmaFeatures": {
-    "jsx": true
+  "parserOptions": {
+    "ecmaVersion": 6,
+    "sourceType": "module",
+    "ecmaFeatures": {
+      "jsx": true
+    },
   },
   "plugins": [
     "react"

Makefile

@@ -23,6 +23,10 @@ extract-styles:
 	@echo "\nExtracting Stilr StyleSheet..."
 	@node -p "var s = require('stilr'); var b = require('./dist'); s.render({}, b.stylesheet)" > ./styles.css
 
+lint:
+	@echo "\nLinting source files..."
+	@$(BIN)/eslint lib/
+
 test:
 	@echo "\nTesting source files, hang on..."
 	@NODE_ENV=test $(BIN)/mocha         \