2.0.6 Stable Designation and #142

Part 1 of addressing #142
Addressing #143

Removed some duplicate language variables and replaced hard coded comma
to global language value. Thanks @Destroy666x
New Avatar Constraint on Maintain Aspect Ratio 

This may be a matter of preference, but it is an edit that I put in whosonline.php for my own website since I prefer it, and I thought I would share the code so you can see if you also prefer it. :)

The default method for maintaining aspect ratio (constraining by width) can result in skewed avatar dimensions for avatars that are significantly higher than they are wide (i.e. an unusually high avatar appears much larger than an unusually wide avatar).

Instead, I prefer to have the script check the avatar's dimensions, and constrain it by its largest dimension. So if the avatar is higher than it is wide, it will be constrained by height. If it is wider than it is high, it will be constrained by width. This avoids avatar stretching while getting closer to the benefit of constraining by both dimensions (uniform avatars).

I also changed $db->query to $db->write_query, since the MyBB Docs indicate that write_query is now preferred (http://docs.mybb.com/Database_Constants.html). Though if you have reasons I'm not aware of for using $db->query, obviously you can ignore that change.
Updated version number and userlist table alignment
Merge pull request #147 from Tanweth/patch-1

New Avatar Constraint on Maintain Aspect Ratio
Fixes CSS Error on #147

Just to be fair, this is Tanweth's pull request but my error :D
Addressing #146

. . . where side boxes that are globally available were placed ahead of
script-specific side boxes regardless of display order.
Addressing #145

. . . where a work-around for the MyBB 1.6.11 language system bug is no
longer needed and should be removed to prevent language issues in older
versions of the plugin language file.
Addressing #148

where the theme exclude list would not save if being cleared.
Added entry for 'Complete List'
Replaced "Complete List" with language file entry

The original file had a "Complete List" entered directly into the template. I added an entry to the asb_addon language file for it and referenced the language entry instead.
Merge pull request #151 from Tanweth/patch-1

Replace "Complete List" with language file entry (Who's Online)
Addressing #149

where neither `radio` or `php` type settings would display due to an
omission on my part.

Also cleaned up the function a bit and removed unnecessary elements.
Addressing #152

where using `htmlspecialchars_uni()` prevented module's from using HTML
in the description
2.0.6 Pre-release

and bringing us up to the new year finally.
Merge pull request #153 from WildcardSearch/stable

2.0.6 Release