Some link issues in README.md

[vsemozhetbyt]

I am not sure how to fix them, so there is just a report.

1. Possibly outdated hashes:

   Popular JavaScript Coding Conventions on GitHub
   Read ECMA-262’s note on this issue

2. ERR_CONNECTION_TIMED_OUT

   Dustin Diaz

3. ERR_CONNECTION_REFUSED

   Draft ECMA 2015 (ES6) Spec

4. 404 Not found

   3Blades/javascript
   bisk/javascript
   gawkermedia/javascript
   huballin/javascript
   kickorstick/javascript
   muber/javascript
   natgeo/javascript
   reidev/js-style-guide
   springload/javascript

[ljharb]

http://sideeffect.kr/popularconvention/#javascript is as up to date as is needed at this time (and the hash still works); the spec link was removed in ES6, so I'll remove it here.

I've removed 2 and updated 3. For 4, I've updated all those links to point at the username instead of the former repo.