Don't create an intermediate list of result fragments (contains debug code)
Shift more work into the consumer thread to build bigger work chunks.
Remove debug code from previous commit.
Make the aggregation constraint optional instead of removing completely so that nodes may propogate the requirement to intermediate nodes.
Don't set IVY_SHARED_DEFAULT_ROOT in advance of the logic that selects the windows/linux form. A clean install for OpenGamma developers will otherwise use the public mirrors instead of the faster local caches.
Allow summation (to zero) at empty nodes.
Job execution result cache has to contain an entry for all values, not just terminals.