Fixed project model import in `bb_tasks` models module.
Fixed circular import in `bb_tasks`.
`tasks` factory models fixed.
Set up `locmem` backend for email testing.
`task_id` field added to `TaskMember` to relate members with tasks.
Fixed `task_id` field to be nullable.
Fixed tests for bb_projects, deleted old tests (related with old models), fixed serializers and tests
Cleaned comments
Fixed signal handlers for `bb_tasks`.
Tasks mailing signal handlers refactored.
Mailing unit tests fixed.
Model test removed (useless because it is already tested by the factory
models).
Merge pull request #246 from jose-lpa/refaktor

`bb_tasks` app fixes
Renamed templates directory for `contact` application.
Fixed includes in `bb_organizations/base.hbs` template.
Compression deactivated in testing settings.
Core API URLs explicitly specified.
#354 start renaming api paths in ember
WIP fixing the api tests for news and remove old broken tests
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