camera: low latency preview and picture

- Take pictures by pressing "s" when the preview opens.
- Depends on sxmo_autorotate.sh
- movie is not currently working. See comments in code
- uses sxiv for image previews of photos taken during that photoshoot
- TODO: use sxiv keyhandlers to add a delete photo function
	- See: /usr/share/examples/sxiv/key-handler
	- I dont know how we would distribute this

scripts/core/sxmo_appmenu.sh

@@ -176,6 +176,7 @@ programchoicesinit() {
 		 Rotate ↻        ^ 1 ^ key greater
 		 Flip ⇄          ^ 1 ^ key question
 		 Flip ⇅          ^ 1 ^ key bar
+		 Thumbnail ⊡     ^ 0 ^ key Return
 		"
 		WINNAME=Sxiv && return
 	elif echo "$WMCLASS" | grep -i "st-256color"; then