Small updates and some minor fixes
- New
mqtt_reconnect()
function to terminate session and trigger reconnect courtesy of @markrad - Headers are now C++ compatible courtesy of @markrad
- Added mechanism to specify own PAL header courtesy of @vpetrigo
- OpenSSL example for windows courtesy of @learn-more
- Minor fixes for CMakeLists for Windows courtesy of @learn-more
Additional contributions by @vpetrigo, @kokke, @timgates42