Allow the "back" button of the MK page to go to a specific MK

[michbarsinai]

Requires having the MK <li>s in an <a> with a name.
Might also consider adding a :focused selector to the MK <li>.

[michbarsinai]

Will partially be solved by #16

[michbarsinai]

Deferred - issues with the fixed nav bar make this non-trivial.