revise certain @container properties for @these #249

Most properties works as if they were distributed to each elements of the group so in these cases it's equivalent to @this.property.

There are properties that are set/retrieved as a whole (as if we were setting/retrieving them on a element containing all the elements matched by @these):

margin
mask
outerHeight
outerWidth
alignXY
anchorXY
border
orientation
ratio

There are also read-only properties that are disabled:

overflows
tag
innerHeight
innerWidth
depth
dpi
dpcm