Fix h1 end tag in Sphinx header titles

A </h1> end tag was incorrectly written as <h1>.  Also adjust style
settings so that the resulting computed style remains the same for
div.rel.

ticket: 7557 (new)
target_version: 1.11.1
tags: pullup
Fix typos in layout.html

There were multiple misplaced semicolons, etc.

ticket: 7558 (new)
target_version: 1.11.1
tags: pullup
Fix "search" accesskey in layout.html

The accesskey for the "search" link conflicted with the one for the
"contents" link.

ticket: 7559 (new)
target_version: 1.11.1
tags: pullup
Consolidate style settings in kerb.css

Move style settings that were previously in layout.html to kerb.css.
Rename kerb.css kerb.css_t, making it a template, to allow
parameterized style settings to remain parameterized.
Reduce copied code in layout.html

layout.html unneccesarily copied code from the parent
agogo/layout.html content block just to alter the sidebar.  Override
various subblocks of the sidebar instead.
Refactor rellinks formatting in layout.html