Use clear: left; instead of both for menuarea

This will prevent the link listing in top page from being pushed far
down below the sidebar. Thanks to /u/kvsmod for reporting it.
Merge branch 'userstyle'
fix expando button + comment nav in nightmode
hide comment links by default

added variable $hide-comment-links. if set to `yes` will hide links
under comment entry by default and only show them on mouse hover
some cleanup

- make comment links always visible again
- put codeblock with line num style into mixins
- use yes/no value for $show-line-num-in-codeblock
- use default mixins file in userstyle.scss