Two lanterns which cause building problems

[no_io]

Summary:
The pictured wall lanterns are unbuildable and/or strand hearthlings.

Steps to reproduce:

1. Place a buildable object above another. Examples: a wall lantern above a section of fence, or a window above an already existing flower-box.
2. Place a buildable object above, but next to something shorter, like a section of fence.

Expected Results:
Unreachable builds should be flagged as such, and hearthlings should not strand themselves on furniture.

Actual Results:
Eternally pending builds and stranded hearthlings who can’t get down from furniture.

Notes:

Attachments:

Version Number and Mods in use:
develop-3109

System Information:

[genboom]

manually build a ladder and they will be fine

the main problem hearthlings have is their movement limitations
http://discourse.stonehearth.net/t/r572x64-hearthlings-reach-and-movement-limitations/23802