* DomainLists.cs: Trim whitespace before adding the items.

* ExtensionMethods.cs: Slightly rewrite GetOrAdd.
Make Threshold channel specific.
Derp, fixing stupid mistake.
* BooruHandler.cs: Change call to CleanupCharacterTags.

* BooruTools.cs: CleanupCharacterTags now modifies the Character Tag
  array in place.

* Config.cs: Small change.