bug#25610: Implement and document emacs repo branch naming conventions

[Glenn Morris]

Package: emacs
Severity: wishlist

Please implement and document some conventions for the names of branches
in the Savannah Emacs repo. (I actually thought this was documented, but
I guess I'm misremembering.)

Things to consider:
scratch/
feature/
features/     # sigh, with one branch
fix/
old-branches/
other-branches/

Please also consider tidying up existing branches.

There are a few unprefixed branches around right now, eg:
nick.lloyd-bytecode-jit
comment-cache
concurrency-libtask
dima_regex_embedded_modifiers

Ref: http://lists.gnu.org/archive/html/emacs-devel/2015-04/msg01031.html