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.
grab lock during destruction
Merge pull request #391 from linas/master

grab lock during destruction
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
A new version of formulas
that works with convolve but is consistent with what Ben wanted
Merge branch 'master' of github.com:opencog/opencog
fixed a bunch of 'new-line-at-the-end-of-file's
Merge pull request #397 from keyvan-m-sadeghi/master

Interval Algebra, new formulas, revision 2
Move the tests correctly
Induction and Abduction rules
Merge github.com:opencog/opencog
Run a pipeline of rules