[O] IMPORTANT: Back to the two-branches git workflow

[Bastien]

Hi all,

The one-month time frame for experimenting with the 3-branches git
workflow is over and I decided to go back to the 2-branches model,
using maint and master as we did before.

Fixes go to maint and development goes to master.

Here are the reasons:

- The solution for doing the right thing while merging is not to
  multiply branches, but to clearly know whether you have to work on a
  private branch vs. a public one.  The blog recently sent by Nick was
  very convincing wrt this, and it helped me understand Achim's advice
  to *never* commit directly on a public branch.

- The two-way Emacs<>Org syncing is not easier with 3 branches than it
  is with 2-branches.

- Using a dedicated branch for releases is not *that* useful.  Releasing
  using git hooks is not such a good idea: releasing from the server is
  simple enough.

So I deleted the hotfix-7.8.06 branch.  

I cherry-picked useful fixes from there to the maint branch, which is
now ahead of release_7.8.09 by a few commits and will be where I will
release 7.8.10 from.

Please do not rely on this branch anymore and update your refs with 
~$ git remote update

Thanks everyone to bare with me!

Best,

-- 
 Bastien