MDL-31830 course: several management interface improvements

* Tidied up course detail permissions so that user is not shown information they couldn't access elsewhere.
* category link dimming now accounts for course creation as an action as well.
* category single select when in courses view mode is now limited to courses user can action in.
* There is now a check at the start of the management page to redirect to course/index.php if the user isn't able to manage in any category.
* Tweaked navigation again, to give the limited users a navbar structure similar to the system cap'd user.
* Cancelling a category delete now takes you back to the category you were viewing.
* Fixed undefined notice
* Improved placement of course request and approval links.
* Several styling tweaks/improvements to the base theme.
* Several styling tweaks/improvements to the bootstrapbase theme.