Add AtomSpace event publisher documentation
Merge pull request #538 from cosmoharrigan/publisher

Add AtomSpace event publisher documentation
Add fields to AtomSpace publisher JSON types: avOld, avNew, tvOld, tvNew, handle, atom. Refactor message construction. Update unit tests.
Add subscription topics addAF, removeAF for when an atom AV changes and it enters or exits the AttentionalFocus
Update AtomSpacePublisher unit tests with new subscription topics
Update AtomSpacePublisher API documentation with new subscription topics addAF, removeAF. Update all topic message definitions.
Update AtomSpacePublisher API documentation with new subscription topics addAF, removeAF. Update all topic message definitions.
Update AtomSpacePublisher API documentation with new subscription topics addAF, removeAF. Update all topic message definitions.
Update AtomSpacePublisher API documentation with new subscription topics addAF, removeAF. Update all topic message definitions.
Merge pull request #539 from cosmoharrigan/publisher

Add additional topics to publisher for monitoring AttentionAllocation