Remove UTF-8 byte order marker from file/string input.

.eslintrc.json

@@ -184,7 +184,7 @@
         "max-lines": "off",
         "max-nested-callbacks": "error",
         "max-params": ["error", 6],
-        "max-statements": ["error", 26],
+        "max-statements": ["error", 28],
         "max-statements-per-line": "error",
         "multiline-ternary": "off",
         "new-cap": "error",

lib/markdownlint.js

@@ -83,6 +83,10 @@ function uniqueFilterForSortedErrors(value, index, array) {
 
 // Lints a single string
 function lintContent(content, config, frontMatter, resultVersion) {
+  // Remove UTF-8 byte order marker (if present)
+  if (content.charCodeAt(0) === 0xfeff) {
+    content = content.slice(1);
+  }
   // Remove front matter (if present at beginning of content)
   var frontMatterLines = 0;
   if (frontMatter) {

test/byte-order-marker-utf8.json

@@ -0,0 +1,4 @@
+{
+  "default": true,
+  "MD041": true
+}

test/byte-order-marker-utf8.md

@@ -0,0 +1,3 @@
+# Header
+
+Text