Abbreviations instead of full puzzle names in breadcrumbs when window is narrow

[Torgen]

Using the same abbreviation algorithm as #348, but applied to puzzle names in the breadcrumbs. While I have some glass layer magic in my multimeta branch to allow the breadcrumbs to use overflow-x: auto and still have tooltips and dropdowns work, it's better if the breadcrumbs get narrow on narrow screens so the scrolling isn't necessary.