Video posting

Okay, so I've re-done a lot of the code in the background. I still need to work on the spoiler tag, as Chux has mentioned how it doesn't work properly in a certain browser. 

Anyways, on to videos. This has had the biggest change, and was causing problems with the forum when posting. You no longer need to use tags when posting videos. So... with this in mind, I'm removing the video tag in the toolbar as this will no longer work. All you have to do from now on is just post the whole URL.

So, this:

https://www.youtube.com/watch?v=ENmC-odKqmQ

Produces this:
https://www.youtube.com/watch?v=ENmC-odKqmQ

It's not just YouTube videos that can be posted now either. Vimeo and DailyMotion videos also work and should use the same format... just post the whole URL. Haven't tested the other 2 as I don't use them, but the theory is the same.

I will go through the database and fix all previous youtube videos.