chore(swig): fix task src glob

The used glob for src swig files was not matching root files in the
src/docs/pages/ directory.
feat(buttons): implement varying sizes

Implement varying button sizes: tiny, small, large and xlarge.

Closes #17
docs(home): add download button
docs(getting started): fix Dependencies section id

The id of the Dependencies section was pointing to the Package Contents section.
This way, the latter was not accessible via the side menu or title anchor.
docs(navbar): remove unit and visual tests for now

As unit and visual tests won't be available for web visualization -
at least for now -, we better without that links in the docs navbar.
docs(grid): fix Grid Options section id

The id of the Grid Options section was pointing to some invalid section.
This way, the latter was not accessible via the side menu or title anchor.