Add flowgraph API to highlight related instructions.
Add flowgraph API to highlight related instructions.

Vector35/binaryninja-api,joshwatson/binaryninja-api,Vector35/binaryninja-api,Vector35/binaryninja-api,joshwatson/binaryninja-api,joshwatson/binaryninja-api,joshwatson/binaryninja-api,Vector35/binaryninja-api,Vector35/binaryninja-api,joshwatson/binaryninja-api,Vector35/binaryninja-api,Vector35/binaryninja-api