Fix an option, cleanup typos & wording.

[Irets]

Fixed an option with a broken name (delete_allowded -> delete_allowed), various typos and improved wording in the configuration files.

The formatting was a bit weird as sometimes option names would start
"# option"
and sometimes
"#option"
but I didn't choose to act on those.

Compiled the project succesfully and found no run-time issues.

[Irets]

#ffmpeg = False # Set ffmpeg to True if you want to display DEBUG level log of ffmpeg.
#mumble_connection = False # Set to True if you need to debug mumble connection (pymumble lib)
#youtube_dl = False # Set to True if you need debug log from youtube-dl

I was confused why these options did not do anything 'till I removed the comments from ends of the options. (non-boolean values)
Currently you can enable options in this file by removing the preceeding '#' but not with this.
By placing the comments above the options, like with other options in this file, it becomes more intuitive to enable these options.

[azlux]

Theses options activate some debug mode.
Globally, having default with lot of comment is good, but the example config become quite useless with time.