Template: breadcrumb - small fixes

- undefined variable on author page
- wrong html structure on hierarchical page
Template: breadcrumb - category structure

The html structure of multidimensional categories was wrong ($before &
$after was missing).
Display on blog (if not front page)

The breadcrumb should be displayed on the blog page, if it's not the
front page.
Merged: 65e6bf5aed5c88a00b530b8c08c8f7e80299f09f
Small fixes
Merge: master
Fixed: merge conflict
Fixed: merge conflict
Merge pull request #6055 from Ninos/template-breadcrumb

Template: breadcrumb - small fixes