Cannot use objects with signals

[sphaero]

The blender plugin isn't noticed by the NodeEditor and it segfaults on exit. This due to the fact the blender plugin registers all objects as objects containing there own parameters:
capability[_objects][blender_camera][location...., orientation..., lensshift, etc]

We either need the new capabilty organisation using signal ID's or emit_signal needs to account for a hierarchy (this is why these unused methods exists in the top of zocp (#37)

For the latter method probably the emitter argument needs to be a list of keys to the emitter.