Async++ CURL library

This library provides a c++ wrapper around libcurl supporting async usage with c++20 coroutines. It is an addition to async++ which provides general coroutine tasks and support classes.

Tested and supported compilers:

Linux	Windows

In addition the websocket client is tested for compliance with RFC6455 using the autobahn-testsuite project:

Provided classes

• base64 and base64url provides base64 encode and decode helpers
• cookie provides cookie handling and parsing
• executor is used for running a curl multi loop in an extra thread and providing a dispatcher interface for use with defer
• handle is a wrapper around a curl easy handle
• multi is a wrapper around a curl multi handle
• sha1 is a standalone sha1 implementation mainly used for implementing the websocket client
• slist is a wrapper around curl slist's used for e.g. headers. Provides a stl container like interface
• tcp_client is a wrapper using CURLOPT_CONNECT_ONLY to establish a raw tcp/ssl connection to a remote host
• uri provides URI parsing and building
• utf8_validator allows validation of utf8 text for compliance
• http_request and http_response provide a simplified interface to handle for doing normal HTTP transfers
• websocket provides a generic websocket client implementation based on tcp_client