Rename of GoneWild mode and other stuff

* Renamed the "gonewild mode" configuration. (`RESGoneWildEnable` is now `RES_SR_Config/ImageTabs`)
* Site modules were converted to use promises.
* Improved the consistency of switching image tabs.
* Put in an actual fix for tumblr posts not closing.
* Removed  some defunct or rarely used image hosts.
* Flickr now uses oembed.
* Moved the CSS for the Image Viewer to the external CSS file.