Refactor building the graph a bit
Add support for "chosen" courses where it is prioritised for dependencies

That is, for each part of the dependency chain, if it evaluates to true,
only the parts that contributed to the true value would be shown.

Also provide buttons for toggling chosen and completed courses
Automatically uppercase search queries
Use current settings when settings dialogue is opened

As opposed to the settings when the page was opened
Add support for showing a link to the original handbook page