Import only less mixins to avoid reapplying reset

topcrashers and explosive signature reports import base.less to get access to
the contents of mixins.less, which causes reset to get reapplied and overwrite
some of the settings in screen.less

Switch to importing only the necessary mixins class brings these two reports
in line with the visual appearance of the other reports.
Clarify supuser permissions

This sets up some switching so that superusers no longer have individual
permissions enumerated, since they implictly have all permissions. This avoids
the confusing situation where a superuser is told "you have all permissions"
and then told about some missing permission because of the group the user
account is in. Since we honor superuser status over group status, avoid
confusing the user and display that first.
Merge pull request #2448 from lonnen/1087298-permissions

Clarify supuser permissions
Merge pull request #2445 from lonnen/1087287-mixin-imports

Import only less mixins to avoid reapplying reset
remove the defunct .notitle html class

fixes 1087295

The HTML class .notitle exists only in templates, and is unused by CSS or JS. This patch removes it, and where adds missing title elements where appropriate