Refactor tlsobs main routine.

[bernata]

Invoke postScan to post to scan endpoint instead of having the code inline.
Added tests for postScan and building url to scan endpoint.

Checklist

• Run make, gofmt and golint your code, and run a test scan on your local machine before submitting for review.
• Workers needs an AnalysisPrinter, registered via worker.RegisterPrinter() (which is separate from worker.RegisterWorker()), and imported in tlsobs (example).
• When adding new columns to the database, also add a DB migration script under database/migrations named the next release (eg. if current release is 1.3.2, migration file will be 1.3.3.sql).
• When new columns require data to be recomputed, add a script under /tools (example) that updates the database and will be run by administrators.