Summary:
So you have unorganized files, or pseudo-organized files, and you dump them into rage. A song or video comes up that you don't want to bother with, so you want to hit delete to not play it.
This will be more useful later with a "loop all" feature, but I implemented it now because I often bump into this situation.
Reviewers: etrunko, raster
Projects: #rage
Differential Revision: https://phab.enlightenment.org/D1486
* also fix mem leak in not freeing vid struct content
these thumbnails are generated in the bg by rage_thumb and will appear
once generated (or already found cached). it'll generate new thumbs if
modified dates are equal or newer on tthe src vs the thumbnail cache.
the caches store 160xN thumbs (keep aspect) with 70% lossy jpeg
quality in an eet file with one thumb per 10 second interval. so it
has limited accuracy.