Fixes#4040
* The TCP connection is now shutdown after OnBodyFinished
* Any open connections are closed when cNetworkSingleton::Terminate() is called.
* Removed ownership cycles in cUrlClientRequest
* Added a check to the test to ensure there are no leaks.
* Renaming changes:
* macro prefix "POLARSSL" -> "MBEDTLS"
* functions now prefixed with "mbedtls_"
* rename PolarSSL++ -> mbedTLS++
* rename polarssl submodule
* Use mbedtls' AES-CFB8 implementation.
* Add cSslConfig to wrap mbedtls_ssl_config
* Update cTCPLink and cBlockingSslClientSocket to use cSslConfig
* Use cSslConfig in cHTTPServer
* Use cSslConfig for cMojangAPI::SecureRequest
* CI Fixes
* Set -fomit-frame-pointer on the right target
