Disallow assignment to native objects or read-only global variables (…

…no-global-assign)

Fixes: standard/standard#596

eslintrc.json

@@ -70,6 +70,7 @@
     "no-fallthrough": 2,
     "no-floating-decimal": 2,
     "no-func-assign": 2,
+    "no-global-assign": 2,
     "no-implied-eval": 2,
     "no-inner-declarations": [2, "functions"],
     "no-invalid-regexp": 2,