Allow players to edit the titles of their threads

As the forums develops and new sections are added, threads will likely be moved to fit into their respective sections.

For example, right now I have a forums game post up in the "Off-Topic" section. If a "Forums Games" specific channel was ever created, it would be appropriate to move that thread into the forums games channel. After that, it would be similarly appropriate if I had the option to remove the "Forums Game:" part of its title, since it is now self explanatory that it is a forums game, since it is in this new section.

And just generally, it's nice to be able to edit the title of your thread if you realize you've made a mistake after posting it, instead of having to delete it and create a new thread entirely. Especially if others have already replied to it, and deleting the entire thread would delete their responses.