Glass panes/iron bars connected to a block have an incorrect collision box.

Steps to reproduce

1. Create the first setup as shown in glass_colbox_missing.png.
2. Stand on top of the lower set of glass panes, and attempt to sneak past the top glass pane.

Notice that you can sneak past the top glass pane. This indicates the collision box for the glass pane state is incorrect - the particular collision box is 8 pixels long, shorter than the 9 pixels that can be visually seen.
This also applies to the "corner" glass pane state, where there is a missing 1x16x1 collision box.

Suggested fix

Either:

• Lengthen the collision box of the "long" glass pane collision boxes (NSEW) by 1 pixel, or
• Add the "middle" 2x16x2 collision box to all other glass pane states.