Fix a major backchaining bug
Filter out some semantically meaningless rule applications
Merge github.com:opencog/opencog
Merge github.com:opencog/opencog
fix more minor Rule bugs
Merge pull request #389 from jadeoneill/master

PLN doesn't get errors and the chainers seem to work
unlock before issuing signal
unlock when sending the remove signal too.
Merge pull request #390 from linas/master

signals should be delivered with locks unlocked.
Refactor so backchaining can handle all the special cases (maybe)
grab lock during destruction
Merge pull request #391 from linas/master

grab lock during destruction
Test backward chainer
PLN Rule names are less ambiguous
Merge pull request #392 from jadeoneill/master

Fix backward chainer
Move PLN tests to normal directory
Add diagram of a time interval
Merge pull request #395 from linas/master

Add diagram of a time interval
atomspace: fix deadlock

This cures issues #393
Merge pull request #396 from linas/master

atomspace: fix deadlock