Refactor title-reply JavaScript

I've also consolidated a fair amount of (post|topic)-reply JS to 'loadReplyForm'
loadReplyForm (and it's brothers and sisters) are behemoth functions that may be
trying to a bit too much at once, but for now, they work fine.

Change-Id: I8023716ef38b18a88ed5fcd8f30a41b8a9a5bb2c
Merge "Refactor title-reply JavaScript"