Changes (since version Kj):
- added support for HTTP OPTIONS method [issue reported by Popov@snb]
- added experimental support for HSTS
- added a new counter 'slc' that counts the number of clients who disconnect without sending any data. It usually indicates clients not have ca.crt installed.
- added new counter 'cly' - client disconnect before response sent
- fixed certificates generated for erroneous domains under extreme load
- fixed crashes when non-SNI requests are received [reported by Popov@snb]
- fixed crashes when null requests are received while logging enabled
- fixed delay in certificate generation
- fixed potential duplication in certificate generation
- fixed description of counter 'err' and 'cls'