Jupyter notebook

- Add: imports.py
- Update: Refactored a lot of code from notebook into imports.py
- Update: For each operation, deleted all cells except for 1 example.
- Update: Added markdown explanations to jupyter notebook
- Delete: start-jupyter.sh: In favor of running it per new instructions in README.md / GitHub home page.

Misc
- Docs: Updated readme.md w/ setup steps
- .gitignore: Updated
- requirements-unlocked.txt: Variation of requirements that are not versioned and don't include transitive dependencies.

.gitignore

@@ -127,3 +127,9 @@ dmypy.json
 
 # Pyre type checker
 .pyre/
+
+# IDEs
+.idea/
+
+# Custom
+cache/