ui-repolist: Add "section-sort" flag to control section sorting.

[Jason A. Donenfeld]

> commit c2926c0642ed869c6bba7108bf092a49a0437526
> Author: Tobias Bieniek <Tobias.Bieniek at gmx.de>
> Date:   Tue Oct 9 20:53:29 2012 +0200
>     ui-repolist: Add "section-sort" flag to control section sorting.
>
>     Flag which, when set to "1", will sort the sections on the repository
>     listing by name. Set this flag to "0" if the order in the cgitrc file
>     should be preserved. Default value: "1".

Committed into a branch that will likely make it to the next release:
http://git.zx2c4.com/cgit/commit/?h=tb/section-sort