Merge pull request #173 from alirezas/master

Fix code tag in markdown exporting

Author: sofish

src/pen.js

@@ -830,6 +830,7 @@
     li: [/<(li)\b[^>]*>(.*?)<\/\1>/ig, '* $2\n'],
     blockquote: [/<(blockquote)\b[^>]*>(.*?)<\/\1>/ig, '\n> $2\n'],
     pre: [/<pre\b[^>]*>(.*?)<\/pre>/ig, '\n```\n$1\n```\n'],
+    code: [/<code\b[^>]*>(.*?)<\/code>/ig, '\n`\n$1\n`\n'],
     p: [/<p\b[^>]*>(.*?)<\/p>/ig, '\n$1\n'],
     hr: [/<hr\b[^>]*>/ig, '\n---\n']
   };