Refactor citation + tags and update README.md

README.md

docs/README.jinja.md

docs/build_docs.py

docs/index.png

examples/cs101_instructor/b_tag.py

examples/cs101_instructor/f_tag.py

examples/cs101_instructor/i_tag.py

examples/cs101_instructor/o_tag.py

examples/cs101_instructor/references.py

examples/cs101_instructor/s_tag.py

examples/cs101_output/homework1.py

examples/cs101_output/i_tag_a.shell

examples/cs101_output/i_tag_b.shell

examples/cs101_output/o_tag_a.txt

examples/cs101_output/o_tag_b.txt

examples/cs101_output/s_tag.py

examples/cs101_students/b_tag.py

examples/cs101_students/f_tag.py

examples/cs101_students/i_tag.py

examples/cs101_students/o_tag.py