Removed many global dictionaries and adopted a convention-over-configuration approach
Merge branch 'master' of github.com:gem/oq-engine into remove_dictionaries_2
Merge branch 'master' of github.com:gem/oq-engine into remove_dictionaries_2
Improved a docstring
Merged from master
Addressed several points raised by Luigi in the pull request #1035
Used get_calculator_class once more
Moved validate into job.validation
Removed some duplication
Fixed a typo in docstring
Merge pull request #1035 from gem/remove_dictionaries_2

Removed many global dictionaries and adopted a convention-over-configuration approach