[chora] Specifying Horde File Root

[Flanakin Michael C SSgt HQ SSG/ENED]

I just moved Chora out of the Horde directory. In order to make this
work, I had to change line 14 of base.php (defines HORDE_BASE). I would
prefer that this be moved to the config directory. What do you guys
think about either adding a setting to the prefs.php, creating a new
config file, or better yet add something into the conf.php for it. I
imagine that not too many people have wanted to change this, but it is
definitely a nice option to have in my opinion. The first two options
are trivial, but I'd have no idea how to attack the third (although I
haven't even tried to figure it out). Let me know what you guys think
would be best and/or whether you think it's something even worthwhile.

Michael