refactored out helper method for using GroundMotionValuesCalcGetter
renamed get_for_hazard to get_assets_data
removed "overkill" import of cpickle with fallback to pickle
renamed slice to subcollection
added HFMonitor
Merge pull request #1234 from matley/risk-from-ses

Compute ground motion values from Stochastic Event Set in a risk calculation
Merge branch 'master' of https://github.com/gem/oq-engine into risk-base-calc-refactoring
fixed tests. renamed HFMonitor
Merge pull request #1237 from matley/risk-from-ses

Updated tests to the new interface of ```openquake.engine.db.models.SiteCollection```
Merge branch 'master' of https://github.com/gem/oq-engine into risk-base-calc-refactoring
all qa tests pass
initial import of loaders_test and validation_test