Sorry I do not have time to provide you with the exact code.
However as jjj already said there are tons of examples on Google.
http://ottopress.com/2010/wp-quickie-kses/
No you should not edit core (*ever*), you should use the filter that is available in the code you just posted bbp_get_allowed_tags.
You need to look into filters https://codex.wordpress.org/Function_Reference/add_filter
Yes, its definitely possible. You will need to make a backup of you all your files and a backup of your mySQL database.
You will need to change the DB depending if the domain will be the same or not.
You can filter it using the bbp_get_allowed_tags filter bbPress provides.
It depends on what your setup is, however you should be able to put this in your theme’s function.php and get it to work. The reason I know this is because I’m doing it on one of my bbPress installs.
add_filter( 'bbp_get_single_forum_description','ja_return_blank' );
add_filter( 'bbp_get_single_topic_description','ja_return_blank' );
function ja_return_blank() {
return '';
}
No problem.
Hopefully in a future release (2.2) this will be a bit easier and their will be some direct filters in place 
This is fixed in the upcoming 2.1 release
Thanks for the link to the plugin. Feel free to start a new thread about it, locking this one as its 4 years old
Quoting is something we have on our radar for core. Hopefully for 2.2.
As far as the existing posts parsing the html in the editor, I ran into that problem myself today. We’ll look into that.
For reference, here’s is how I was able to replicate this:
Use a link in the editor when making a post, eg:
<a href="http://bbpress.org">bbPress</a>
Everything seems fine. Until you go back and edit the post and then are presented with
http://www.jaredatchison.org/files/Screen%20Shot%202012-03-02%20at%205.49.44%20PM-OTIItv7mSR.png
I’m I really can’t say because I use SVN to sync up with the latest version. Maybe jjj will have some input.
I don’t think there is an easy way to do this, unfortunately, outside of writing a custom plugin.
Actually it’s my fault. I originally listed my plugin as 2.0 and 2.1 compatibly, when really it only works for 2.1 (which is currently in beta).
Without a link to your site I can’t say.
To be honest I still don’t understand what isn’t working. Place the bbpress.css in your theme directory, edit it as you need, that should be it.
Closing. jjj moved it to Future Releases. Patches welcome 
1. Unfortunately right now, without writing a plugin, there is no way accomplish this. So if you make someone a moderator, they will be a moderator for the entire site.
2. I’m not 100% sure on the compatibility with bbPress, but I would try https://wordpress.org/extend/plugins/simple-local-avatars/
That would be nice, my concern would be the performance hit – though jjj would have better input on this.
Sorry, I’ve been closing threads that are “done” due to getting bumped by spammers. Hopefully when the site gets upgraded to 2.1 this won’t be an issue.
I deleted the snippet because it is now a full plugin available here
https://wordpress.org/extend/plugins/bbpress-custom-css-file/
Awesome, thanks for reporting back. If you find any bugs please come back and report them
Go to Tools > Recount I believe.
Feature request like this I would just submit a ticket for and put in Awaiting Review, then jjj can either approve and put in Future Releases or punt with an explanation.
For the record I agree, it would be a nice feature in core. I have seen a plugin that does this but from my research it seems to be flaky.
My recommendation https://wordpress.org/extend/plugins/simple-local-avatars/
Not 100% sure it will work with bbPress, but it *should*.
There is a “Recent Activity” widget that comes with bbPress – typically I just use that
