#40 Improve URL/link detection

[fritzophrenic]

Use a more intuitive URL detection, or allow to specify regex to detect URLs with a new option. The regex currently in use picks up parentheses for example. This is valid sometimes, because parentheses are allowed in URLs. For example many Wikipedia articles have an embedded (...) group. But sometimes it is obviously not desired, like with "Follow this link (https://example.com/)" it will pick up the closing parenthesis.