Freezes in 0.13.10 and crashes in 0.13.11 (line 105 of control.lua)

Underground belts frequently cause nearby belts to incorrectly be registered as overflowing.

Belts stop overflowing after saving / loading.

Red squares indicating potential overflow remain after saving / loading even when the corresponding belt is removed.

Screenshots of these bugs and others: https://imgur.com/a/PDRVT

continues to crash in 0.13.19...

placed my first ever belt, immediate crash

Notice

Error while running event on _built_entity (ID 6)
An area of zero size is not supported. Leave the
area nil to search the entire surface.
stack traceback:
belt-overflow/control.lua:105: in function
'terminal_belt_lines'
belt-overflow/control.lua:316: in function
'check_and_update_entity'
belt-overflow/control.lua:350: in function
'check_and_update_posd'
belt-overflow/control.lua:396: in function
'check_and_update_neighborhood'
belt-overflow/control.lua:408: in function
'onModifyEntity'
belt-overflow/control.lua:413: in function
<belt-overflow/control.lua:412>

I will rewrite this from scratch for 0.15. Thanks for the reports.

I have fixed at least half of the bugs in your photos. Thanks for the great bug report. I'll be releasing an 0.15 version shortly.