Cleanup of backward-chainer after use
Cleanup of backward-chainer after use

rTreutlein/atomspace,AmeBel/atomspace,rTreutlein/atomspace,AmeBel/atomspace,rTreutlein/atomspace,AmeBel/atomspace,rTreutlein/atomspace,rTreutlein/atomspace,AmeBel/atomspace,AmeBel/atomspace