Just two minor details. I cannot comment on the implementation.
Shouldn't this return something?
Mhmmm, bool or eina error, i can imagine that it is helpfull to know the difference between "Property does not exist" and "Hey, you already binded that"
Rebase, and change the return to be an Eina.Error and forgot to update the commit message (will do if that if it is the only missing bits)
My concerns have been addressed, but I still cannot comment on the implementation.