Update dead links (#321)

README.md

@@ -1756,7 +1756,7 @@ Handy metrics based on numbers above:
 * [Box Blogs](https://blog.box.com/blog/category/engineering)
 * [Cloudera Developer Blog](http://blog.cloudera.com/)
 * [Dropbox Tech Blog](https://tech.dropbox.com/)
-* [Engineering at Quora](http://engineering.quora.com/)
+* [Engineering at Quora](https://www.quora.com/q/quoraengineering)
 * [Ebay Tech Blog](http://www.ebaytechblog.com/)
 * [Evernote Tech Blog](https://blog.evernote.com/tech/)
 * [Etsy Code as Craft](http://codeascraft.com/)
@@ -1776,9 +1776,8 @@ Handy metrics based on numbers above:
 * [Microsoft Engineering](https://engineering.microsoft.com/)
 * [Microsoft Python Engineering](https://blogs.msdn.microsoft.com/pythonengineering/)
 * [Netflix Tech Blog](http://techblog.netflix.com/)
-* [Paypal Developer Blog](https://devblog.paypal.com/category/engineering/)
+* [Paypal Developer Blog](https://medium.com/paypal-engineering)
 * [Pinterest Engineering Blog](https://medium.com/@Pinterest_Engineering)
-* [Quora Engineering](https://engineering.quora.com/)
 * [Reddit Blog](http://www.redditblog.com/)
 * [Salesforce Engineering Blog](https://developer.salesforce.com/blogs/engineering/)
 * [Slack Engineering Blog](https://slack.engineering/)