Experimental ZMQ interface Support

Allow access to the multimodal iSAM SLAM solution to any variety of programming languages via a ZMQ and formal JSON marshaling interface. This an experimental release, but mutli-language support is intended as a long term objective of this project. Also note that Julia itself uses statically compiled code and allow the compilation of conventional shared/static objects .so or object files .o that can be combined with C or C++ in the same way as any other library. For relevant work in this release, please see milestone labels here.