* BooruTools.cs:
* DanboTools.cs:
* UrlTitling.csproj: Moved DanboTools to the more correctly named
  BooruTools.

* BooruHandler.cs: Made BooruHandler abstract, it's not intended to be
  instantiated.

* Config.cs: Added more default Warning Tags. Thanks go to SteelGolem
  for the suggestions.