no methods in element

[littleneo]

I got this when trying your branch :

Traceback (most recent call last):
File "G:\Program Files Shared\3d\blender-2.58a-windows32\2.58\scripts\addons\b
lended_cities\core\ui.py", line 33, in execute
new, otl = city.elementAdd(tag,outlineOb)
File "G:\Program Files Shared\3d\blender-2.58a-windows32\2.58\scripts\addons\b
lended_cities\core\main.py", line 84, in elementAdd
otl_elm.nameNew(outlineName)
AttributeError: 'BC_elements' object has no attribute 'nameNew'

element has no method. I already meet this case let me see.

[littleneo]

in your register-builders barnch you need to register the builder first.
si register_default_builders() in line 50 in init.py fix it
you need to register from childs to root and unregister from root to childs

the little line in italic right above this :
http://wiki.blender.org/index.php/Dev:2.5/Py/API/Overview#Manipulating-Classes