Onioscan-like tests for HTTP(S)-endpoints

Do probing tests for Onion Service sites:

• Much like what Onionscan does.
• With other simple tests to avoid de-anonymization and enumeration of services.

added Onion Services label

marked this issue as related to #37

added Roadmap::Future label

marked this issue as related to #49 (closed)

changed the description

removed Roadmap::Future label

added Icebox label

added Improve tests label