* Add ZeroMQ external submodule

* ZeroMQ libzmq building on macOS

* Added RPC namespace, settings and logging

* Added request queue handling and new classes

* Add C++ interface to ZeroMQ

* Added start of ZeroMQ RPC Server implementation.

* Request construction and callback request handling

* Read and write memory implementation

* Add ID to request format and send reply

* Add RPC setting to macOS UI

* Fixed initialization order bug and added exception handling

* Working read-write through Python

* Update CMakeLists for libzmq to resolve target name conflict on Windows

* Platform-specific CMake definitions for Windows/non-Windows

* Add comments

* Revert "Add RPC setting to macOS UI"

* Always run RPC server instead of configurable

* Add Python scripting example. Updated .gitignore

* Rename member variables to remove trailing underscore

* Finally got libzmq external project building on macOS

* Add missing depende...