added loaders and validation risk module
added validators to every risk calculator
several fixes. all the qa tests pass
moved output generation outside the calculators
Merge branch 'risk-from-ses' into risk-base-calc-refactoring
added output builders to classical risk
Merge branch 'risk-from-ses' into risk-base-calc-refactoring
Merge branch 'master' of https://github.com/gem/oq-engine into risk-base-calc-refactoring
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
fix typo in writer
improved docstring of get_risk_models
added more tests
Merge branch 'master' of https://github.com/gem/oq-engine into risk-base-calc-refactoring
Merge branch 'master' of https://github.com/gem/oq-engine into risk-base-calc-refactoring
merge commit
Merge pull request #1238 from matley/risk-base-calc-refactoring

Risk BaseCalculator refactoring