Missing image extension in the exported COA tools JSON file

I got this error when trying to load the json produced by the COA exporter in COA tools for blender:
Info: leglowerback.png Sprite created.
Traceback (most recent call last):
File "/home/mvl/.config/blender/2.79/scripts/addons/coa_tools/operators/import_sprites.py", line 135, in execute
obj = bpy.data.objects[sprite["name"]]
KeyError: 'bpy_prop_collection[key]: key "leglowerback" not found'

location: :-1

location: :-1

After comparing the json with the one from the example files i noticed their names have a file extension while the exporter does not add this. In this case making "name" : "leglowerback" into "name" : "leglowerback.png" fixed the issue. I changed line 78 in COATools.py to
"name": child.name+".png",
which did it as a temporary fix but as you might have noticed this does not take into account the file extension in the config file. I have not been successful in doing this so i will leave that bit to you guys.

Start in COATools.py around line 78, where the exporter writes each child name into the JSON, and inspect how the config file defines the image extension. Compare the generated JSON with the example files, then test the output through COA Tools for Blender's sprite import path. Done means exported names include the configured extension and the JSON loads without the reported missing-object error.

Written by the indexing model from the issue text.