D.C Style - Thumbnail 1.0.4 Patch Level 1

• Add null safety check for "isContainingMediaBbCode" function in Thumbnail repository (Refer to the case of @otto here: https://xenforo.com/community/threads/d-c-style-thumbnail.185177/post-1677841)

• Add compatibility to XF 2.3

• Fixed error: "thread_id" values must be unique

• Fixed bug threads didn't automatically apply thumbnails in some cases.

• Optimized some CSS.

• Fix minor HTML errors when displaying thumbnail.

Add the possibility to set maximum image dimensions for custom-uploaded thumbnails.

Add the possibility to set whether a thread is "video-thread" (Auto-detect by default). If a thread is set to be video-thread, its thumbnail will have an additional play icon.

• Minor bugs fixed and improved performance.