Add infrastructure for integrating BTOR2 interpreter into Calyx

[obhalerao]

Add the BTOR2 interpreter along with infrastructure necessary for integrating the interpreter with Calyx. I also created a dummy BTOR2Add primitive that reads a hardcoded program from disk and tested it against Cider 2 to ensure correctness of the integration.

[rachitnigam]

This has a lot of generated files (.btor2). Is that intentional? CC @EclecticGriffin

[obhalerao]

This has a lot of generated files (.btor2). Is that intentional? CC @EclecticGriffin

Ah; those files were tests from the old repo I imported the interpreter from. I can remove/refactor those.

[EclecticGriffin]

LGTM. Merge whenever you're ready