[VOTE/lazy] Merging JENA-624 (in-memory transactional dataset)

[Andy Seaborne]

This is a code vote with lazy consensus, deadline Friday midnight UTC 
for PR#94/JENA-624, the new in-memory, transactional dataset implementation.

If no-one objects within three days, I'll assume lazy consensus and 
merge it.


I think it's about time to merge this into the code base. It will be 
easier to do the final adjustments, more testing, Fuseki integration, 
N&L updates, documentation and code cleaning for deprecation cycle below.

For now, it would only be exposed as DatasetFactory.createTxnMem.  We 
need a deprecation cycle to migrate DatasetFactory.createMem and get 
people using the general datasets via DatasetFactory.createGeneral.

        Andy