Added better instrumentation to the hazard getters
Changed two descriptions
Removed the operation 'getting hazard' from the performance table
Fixed some points raised in https://github.com/gem/oq-engine/pull/1189
Merge pull request #1189 from gem/better-instrument-hg

Added better instrumentation to the hazard getters
Merge branch 'master' into smart-block_size
Splitted calc_num_tasks for event based an other calculators