info about notmuch gui 'alot'

[Patrick Totzke]

Hi!

The config syntax changed recently, when I switched from configparser to configobj.
To clarify:

* the new config syntax is explained in the user docs at http://alot.rtfd.org.
  These are auto-generated at each commit and correspond to the `testing` branch,
  which is where the bleeding edge lives.

* both old and new config formats are (based on) INI:
  That means the *do* accept leading spaces, everything after a `#` is a comment.
  The new syntax makes use of nested sections, something configobj can parse
  and configparser cannot.

* both master and testing have switched to the new syntax, but only in testing
  is this actually documented in README/INSTALL.
  https://github.com/pazz/alot/blob/testing/INSTALL.md
  
This is due to me being lazy and that I'm planning to merge testing and master to make a next release soon anyway, so I
did not bother cherry picking that commit. But I'm happy to see that there are enough potential users
to be confused by this and will fix this inconsistency in the docs.

By the way: If you want to be on the safe side regarding the bindings, go for notmuch and its python bindings
from git master instead of potentially outdated versions provided by your distri.

Cheers,
/p