R1:d96d515cc21e

Add comment linking to Maniphest and Differential

Summary:
Allows you to link to comments with "D123#3" or "T123#3", then adds a pile of JS
to try to make it not terrible. :/

The thing I'm trying to avoid here is when someone says "look at this!
http://blog.com/#comment-239291" and you click and your browser jumps somewhere
random and you have no idea which comment they meant. Since I really hate this,
I've tried to avoid it by making sure the comment is always highlighted.

Test Plan:
Put T1#1 and D1#1…