Fixed the initialize_realizations method
Updated the test logictree_test.py
Fixed the classical/core_test.py
Fixed a few missing imports
Merge branch 'fix-initialize_realizations' of https://github.com/gem/oq-engine into fix-initialize_realizations
PEP8 fix
Added warning when num_sampling > num_realizations
Merge branch 'master' of github.com:gem/oq-engine into fix-initialize_realizations
Merge branch 'master' of github.com:gem/oq-engine into fix-initialize_realizations
Added a test for the warning about too many samples
Used logictree.sample_one in the engine
Merge pull request #1472 from gem/fix-initialize_realizations

Refactored initialize_realizations and added a warning when num_samples > num_realizations