updated database schema. scenario demo runs
classical psha risk demo updated
new db schema
updated django models
updated test fixtures
Merge branch 'master' of https://github.com/gem/oq-engine into exposure-update
updated qa tests fixtures
renamed number_of_units -> units
fix typo. non_structural -> nonstructural
renamed non_structural -> nonstructural
added business_interruption vulnerabilty
removed duplication of vulnerability input type names
avoid duplicate imt to be used in hazard calculators when imt are got from risk models
fixed vulnerability_model choices variable
fix parsing of risk models
comments improved
added docstrings
Merge branch 'master' of https://github.com/gem/oq-engine into exposure-update
improve readability
fixed conflict (on a docstring)