Possible race fix for bug #1025
Add a sanity check for multi-atom-table atom removal.
atomspace: clone atoms that belong to other atomspaces.
atomtable: clone the outgoing set too, if cloning needed
Merge pull request #1026 from linas/racey

Possible bug fixes for issue #1025
Atom extraction: add another sanity check.
Merge pull request #1027 from linas/r2

Atom extraction: add another sanity check.
Start work on nested AtomSpaces
AtomTable: more of the environment implementation.
Allow Hierarchical AtomSpaceImpl's
AtomSpace: Remove some strange old cruft.
Merge pull request #1028 from linas/hier

Add support for multiple hierarchical atomspaces
AtomTable: enforce proper link insertion
Extend the multi-atom unit test
Unit test: test hierarchcal atomspaces, too.
Add an atomspace argument to cog-new-atomspace
prepare to expand the multi-atomspace unit test
expand the multi-atom-space unit test
Some multi-atomspace methods for scheme.
multiple atomspace unit test: test new API