Update feature addition focus.

Update interactions.md with the latest feature to be added.
Add initializer spec for AggregateReportGenerator.
Fulfill AggregateReportGenerator#initialize spec.
Subdivide AggregateReportGenerator spec.

Split AggregateReportGenerator between pending JobAggregateReportGenerator and RecruiterAggregateReportGenerator classes.
Fulfill AggregateReportGenerator subdivision spec.

Create JobAggregateReportGenerator and RecruiterAggregateReportGenerator.
Test actual output of JobAggregateReportGenerator.

Add spec for text output of JobAggregateReports generated by JobAggregateReportGenerator.
Add Submission#add_job_to_joblist.
Add SubmissionRecord#add_job_to_joblist.
Fulfill recent JobAggregateReportGenerator spec.

Add JobAggregateReportGenerator#generate_from.

Add JobAggregateReport.
Spec on JobAggregateReportGenerator's job filter.

Add spec checking that JobAggregateReportGenerator generates a report on only the job supplied to its initializer.
Fulfill JobAggregateReportGenerator filter spec.

JobAggregateReportGenerator reports on only the job given to its initializer.
Check that Job report counts multiple applications.

Add spec checking whether JobAggregateReportGenerator reports on the correct number of applications when there are multiple applications for the same job.
Fulfill JobAggregateReportGenerator count spec.

Fulfill spec which tests whether JobAggregateReportGenerator reports the total number of Applications to a Job applied to more than once.
Add TODO item to interactions.md.
Add notes.txt to track general notes.
Correct test description error: wrong word.
Use real RecruiterAggregateReportGenerator test.

Replace initializer test for RecruiterAggregateReportGenerator with one that tests for real results from #generate_from.
Fulfill RecruiterAggregateReportGenerator spec.

Fulfill basic RecruiterAggregateReportGenerator#generate_from spec.
Correct (fulfilled) expanded #generate_from spec.

Correct (fulfilled) spec for RecruiterAggregateReportGenerator#generate_from that checks for multiple submissions.
Update interactions.md with feature additon.