Remove tree and count fields from Context and Query models

Signed-off-by: Don Naegely <naegelyd@gmail.com>
Add count methods to context and query

This includes tests for these methods.

Signed-off-by: Don Naegely <naegelyd@gmail.com>
Merge pull request #245 from cbmi/issue-194

Remove tree/count fields from Context and Query models
Remove model property from context and query

This will require a subsequent change in Serrano

Signed-off-by: Don Naegely <naegelyd@gmail.com>
Merge pull request #247 from cbmi/remove-model-property

Remove model property from context and query
Remove group field from DataField and DataConcept

This was intended for permissioning, however it being superseded
by django-guardian.

Fix #246

Signed-off-by: Byron Ruth <b@devel.io>