Style guide part 6

This replaces the livepipe tabs with jQuery tabs. Please note that this PR is more for the functionality and not the style, which will take effect in a later PR.

This includes tabs on the manage groups/graders pages, spreadsheet graders page, marking panes, and student results panes.

Some of the "tabs" that actually just filter the tables are broken, but those will be changed with @oneohtrix 's new tables anyway.