Fix ExecutionManager.getTasksWithAllTags signature

- Use Iterable<?> instead of Iterable<String> for parameter type
Move EffectorUtils from brooklyn.entity.basic to brooklyn.management.internal
Extract code from AbstractEntity to EffectorUtils

- For effector-invocation
AbstractEntity.parent/application: don't use EntityReference

- field is private and of type Entity, rather than using EntityReference
Add ManagementContext.getEntityManager

- Deprecates methods from ManagementContext.getEntity(id) etc
- Moves methods to EntityManager interface
Update uses of managementContext.getEntityManager().*

- Changed calls to deprecated methods in managementContext, to instead
  use getEntityManager().manage() etc.
- Updates lots of test cases to use Entities.manage(entity) etc
Moves entity-tracking from *ManagementContext to LocalEntityManager
Tidy-up of ManagementContext impl
Merge pull request #449 from aledsage/refactor/AbstractEntity-cleanup

cleanup abstract entity, and extract EntityManager interface