* [ixwebsocket] update to 5.0.6 to fix Windows problem
Some test started to fail on Windows in the 5.0 branch.
```
ERROR: Unable to connect to echo.websocket.org on port 80, error: Connect error: No error
ERROR: Unable to connect to echo.websocket.org on port 80, error: Connect error: No error
ERROR: Unable to connect to echo.websocket.org on port 80, error: Connect error: No error
ERROR: Unable to connect to echo.websocket.org on port 80, error: Connect error: No error
ERROR: Unable to connect to echo.websocket.org on port 80, error: Connect error: No error
ERROR: Unable to connect to echo.websocket.org on port 80, error: Connect error: No error
ERROR: Unable to connect to echo.websocket.org on port 80, error: Connect error: No error
```
We figured it out and fixed it. This issue has more details. https://github.com/machinezone/IXWebSocket/issues/103
* ixwebsocket: update to 6.1.0
* Add ixwebsocket
* remove commented cmake directives
* add dependencies
* directive to remove share folder
* try again with 4.0.3 which is using find_library for external code instead of vendoring it by default
* use vcpkg feature flag to detect ssl backend + compile ws
* do not build ws command line tool
* add a feature for osx / control file closer to curl one
* stop using features, as this makes CI unhappy
* Revert "stop using features, as this makes CI unhappy"
This reverts commit 4666b18567.
* play again with Build-Depends to fix error which appears to be only on uwp
* call vcpkg_from_github instead
* share folder not created
