Version 0.1.9

Version 0.1.9 brings some bug fixes and improvements.

Clients are now safe for concurrent use.

Requests must now be provided with a Context. The NewRequest and
NewRequestFromURL functions will use the background context. A custom
context can be specified by setting the Context property of Request.

Request URLs without a scheme will no longer be treated as if they had a
scheme of gemini.

KnownHosts and CertificateStore internals are now exposed. The structs
KnownHostsFile and CertificateDir have been added and all file system
storage functionality has been moved to them. CertificateDir will also
escape forward slashes in certificate scopes to enable proper storage of
client-side certificates.

Queries in input requests will now be properly escaped. The functions
QueryEscape and QueryUnescape have been provided to facilitate the
proper encoding and decoding of queries.