remove default setting
fix #439
Merge remote-tracking branch 'origin/master' into 1.4.5
I have to commit these to get rid of the "uncommitted changes" because these appear with Windows line feeds and are not resetable for the repo.
move file support registration to player plugin

This is really the proper place. First, without the player, nothing can
be done with the "image". Second, actual support will vary by player.
fix #441
update plugin document for better clarity
Merge remote-tracking branch 'origin/1.4.5' into 1.4.6