Factor more configuration into the dedicated struct
update rust-toolchain
Flesh out Gemini server

Now handles more stuff more carefully, including checking we are
responding to the right scheme and hostname.
Improve command for generating certs
add a config module and a RequestParseError type
remove useless lib.rs
Add constants for Gemini protocol limits

Also actually enforce the limit in the Response::success constructor.
Read Gemini requests by hand to enforce the maximum length

BufRead::read_line will just extend the String you pass it, and also
will stop at a plain \n character, when we really care about the \r\n
pair.  So we just read by hand using the basic Read functionality
until we hit the protocol-specified limit of 1024 or a \r\n pair.
Add request parsing and don't bail after one failed request
Add licence file
Add README with how to generate keys
Get to a basic Hello Gemini implementation
Initialise empty project