Remove unused module include.

UnpostedJob and PostedJob no longer include Filterable.
Test for new application interface.

Update job application submission specs to expect an ApplicationService, use the corresponding methods, and test for applications instead of submissions.
Add Application#valid?.
Add NewSubmission#valid_for?.
Fix resume validation.

Refactor JobApplierRole#apply_to_job to accommodate its role as a delegator instead of a module.

Update #apply_to_job spec to check whether a specific error was raised, as opposed to having something thrown.
Add multi-role spec.

Add spec checking whether a jobseeker, for example, can take on more than role role effectively.
Reimplement JobSaverRole as DelegateClass child.

Reimplement JobSaverRole to inherit from  DelegateClass, taking a specific roletaker in its initializer.
Update specs for changed JobSaverRole.

Update specs and Helpers::saving_jobseeker to use the new implementation of JobSaverRole.
Move role spec to its own file.
Spec describes tested class.

Update role spec to associate it with JobSaverRole, the class it actually tests.
Add JobApplierRole delegation spec.

Add spec checking whether JobApplierRole works when combined with other roles.
Refactor JobApplierRole for delegation.

Refactor JobApplierRole to inherit from DelegateClass instead of Role.
Update Helpers jobseeker methods.

Update ::applying_jobseeker to use the new JobApplierRoleImplementation and drop the old JobApplier class.

Refacto ::saving_jobseeker, removing some unused code.
Remove method/variable ambiguity in spec.
More domain-specific language.

Replace references to "roletaker" with ones to "delegatee" to better reflect how the role classes work.
Document existing features.
Add filter/report integration spec.

Add spec showing the integration of ApplicationsByDateFilter and TextApplicantsReport.
Document feature addition.
Document pending feature.
Add employer job application filter specs.

Add preliminary specs for ApplicationsByEmployersJobsFilter class.

Add placeholder ApplicationsByEmployersJobsFilter class.