#1245592 by e.zeedub: video-thumbnail-url token not working (cherry-picking from commit 18f3afba)

Firefox doesn't support 'focusout' for jquery as of 4.0, replace it with 'blur'. It bubbles though, but who cares.

#1139618: Emvideo provider Youku expects 'embed' parameter for no reason, lets just pass it and get over with.

Fixing the confusion with no checkboxes selected in emaudio/emvideo supported providers description.

by publicmind: Implementing the architecture where plugins will be allowed to process the URL GET parameters of their choice and can show different forms depending upon it.

Supporting the link bookmarklet functionality for the link plugin using the above architecture.

#1053758 by publicmind: replaced IDs with CSS classes, so that multiple forms can bbe styled properly without extra effort.

by publicmind: remove the processed class from the link plugin's URL field once in focus to have the normal CSS for it.

1) Delete the thumbnails upon deletion of status.
2) Store only the fid's of thumbnails instead of full file object

by publicmind: fix the issue with merging default parameters which were causing the video to be not converted and video thumbnails were not generated (without custom command line options for ffmpeg). Also fixed the update for converted video files.

by publicmind, pribeh: modified the link plugin's selection form to make it look similar to FB, modified the JS and CSS.

#964808 by publicmind, pribeh: Putting the final pieces of CSS to overlay the play icon over the video thumbnail and polish the 'inline video replacement' feature.

by publicmind: changing the 'data' field to medium text for MySQL, as 'emvideo' integration tries to store about 250KB of data.

feature by publicmind: inline thumbnail replacement by video for the embedded videos by link plugin.

#964802: Adding an extra div for the plugin icons to get the hover effect and enabling the 'Attach:' text by default.

Include the following CSS, to hide the 'Attach:' text:
.fbsmp-attach-text {
  display: none;
}