Generate svg wheel. Embed svg in index.html.
Show number of packages with wheels. Close #18.

Refactor angle code to work with arbitrary package counts.
Remove javascript wheel. Change fraction style.
Update fraction text colour to match page style.
Add title text to each sector of wheel.

Refactor fraction code into `add_fraction` function.
Replace fixed height and width with viewBox.
Refactor headers and path into multiline strings.

Use nicer spelling to count wheel packages.
Remove magic numbers.
Merge pull request #21 from Ian-Foote/svg_wheel

Generate svg wheel. Embed svg in index.html.