Parallized the INSERT INTO gmf_agg query by introducing a mapreduce facility
Merge branch 'cleanup-engine-logs' of github.com:gem/oq-engine into parallelize-insert-into-gmf_agg
Small fixes
Used map_reduce also in the classical post_processing
A small but essential fix
Made _map_reduce private and added a parallelize function
Removed the old distribute function
Improved docstrings and added a comment
Fixed two QA tests
Added a forgotten argument
Merged from master
Merge pull request #1174 from gem/parallelize-insert-into-gmf_agg

Parallelize insert into gmf_agg table