Add visit obs, person condition and person obs

Add models and materialized views for observations through visit and
person as well as conditions through person. Create models for harvest
that will use those views. Include views and models for observation and
condition concepts and type concepts.

Signed-off-by: Aaron Browne <aaron0browne@gmail.com>
Add matviews and correct models for new domains

Add materialized views for visit observation, person observation, and
person condition domains. Correct the use of the '_id' suffix on field
names on the new models depending on whether they are defined as
foreignkeys or not.

Signed-off-by: Aaron Browne <aaron0browne@gmail.com>
Merge pull request #88 from cbmi/develop

Add additional data domains