Floating effect now uses animate() instead of pixel_y while loop thingy.

Distinct actions that indefinitely change a mob's pixel_y or pixel_x, like strapping someone to a roller bed, should also alter new variables old_y or old_x accordingly. This means that floating and jittering animations no longer interfere, as the animations use old_x/old_y as the "base" position.

Entering areas with gravity from areas without grabity now removes floating effect.

code/game/objects/structures/stool_bed_chair_nest/alien_nests.dm

@@ -16,6 +16,7 @@
 					"<span class='notice'>[user.name] pulls you free from the gelatinous resin.</span>",\
 					"<span class='notice'>You hear squelching...</span>")
 				buckled_mob.pixel_y = 0
+				buckled_mob.old_y = 0
 				unbuckle()
 			else
 				buckled_mob.visible_message(\
@@ -25,6 +26,7 @@
 				spawn(1200)
 					if(user && buckled_mob && user.buckled == src)
 						buckled_mob.pixel_y = 0
+						buckled_mob.old_y = 0
 						unbuckle()
 			src.add_fingerprint(user)
 	return
@@ -52,6 +54,7 @@
 	M.dir = src.dir
 	M.update_canmove()
 	M.pixel_y = 6
+	M.old_y = 6
 	src.buckled_mob = M
 	src.add_fingerprint(user)
 	return

code/game/objects/structures/stool_bed_chair_nest/bed.dm

@@ -195,6 +195,7 @@
 	if ( !ismob(M) || (get_dist(src, user) > 1) || (M.loc != src.loc) || user.restrained() || user.lying || user.stat || M.buckled || istype(usr, /mob/living/silicon/pai) )
 		return
 	M.pixel_y = 6
+	M.old_y = 6
 	density = 1
 	icon_state = "up"
 	..()
@@ -204,6 +205,7 @@
 	if(buckled_mob)
 		if(buckled_mob.buckled == src)	//this is probably unneccesary, but it doesn't hurt
 			buckled_mob.pixel_y = 0
+			buckled_mob.old_y = 0
 			buckled_mob.anchored = initial(buckled_mob.anchored)
 			buckled_mob.buckled = null
 			buckled_mob.update_canmove()