* Fix and optimize content type sniffer
- Minimize copying and buffering
- Ensure it sniffs the full 512-bytes prefix
* Fix assorted warnings
* Cleanup error formatting
- Remove unnecessary formatting calls
- Fix invalid format strings
- Standardise logging calls
* Fix and optimize index fallback method
- Pass through non-404 responses correctly
- Do not buffer original response
* Test content sniffing and index fallback
* Update changelog
* Remove obsolete check
* Add safety checks in sniffer
