Exposure schema

This pull will update the GEM exposure export tool views to reference the new GED2 schema. Please note that views.py includes reference to the Ged2-test namespace. This is to be changed future version of the GED schema. Also note that the views.py is currently hard coding the time of day table geographic_region_id. Final note: this bug contains no new features.

Launch pad bug: https://bugs.launchpad.net/oq-platform/+bug/1179968