GRC: Standalone application and pluggable workflows

This project's goal is to make GRC as a stand alone application, separated from GNU Radio code base and make the workflow pluggable. The main goal of this project is broken down into several milestones that is, separation of GRC from GNU Radio code base, modularized option block, modularized templates, and jinja template support. The project intends to let people define their own workflow so that people can generate code from the flow graph that is created in GRC into any programming language and can make use of different GUI frameworks. Another main goal of this project is to support jinja template for code generation besides mako template.