documentation for making git add only annex when configured by annex.largefiles

Code change should be trvial, but not yet implemented. This
significantly complicated the task of documenting how git-annex works.

I'm not sure how useful the annex.gitaddtoannex confguration is after
this change; seems that if a user has an annex.largefiles they will want
it applied consistently. But the last thing I want to hear is more
complaining from users about git add doing something they don't want it
to.

There's a pretty high risk users who got used to the git add behavior
and don't have annex.largefiles configured will miss the NEWS and
complain bitterly about their suddenly bloated repositories. Oh well.

Removed outdated comments about the old behavior to avoid confusion.
I don't know if I've found all the places that griping spread to.

doc/tips/largefiles.mdwn

@@ -1,8 +1,7 @@
 [[!meta title="annex.largefiles: configuring mixed content repositories"]]
 
-Normally commands like `git annex add` always add files to the annex.
-And when using the v7 repository mode, even `git add` and `git commit -a`
-will add files to the annex.
+Normally commands like `git annex add` always add files to the annex,
+while `git add` adds files to git.
 
 Let's suppose you're developing a video game, written in C. You have
 source code, and some large game assets. You want to ensure the source
@@ -10,14 +9,17 @@ code is stored in git -- that's what git's for! And you want to store
 the game assets in the git annex -- to avod bloating your git repos with
 possibly enormous files, but still version control them.
 
-The annex.largefiles configuration is useful for such mixed content
-repositories. It's checked by `git annex add`, by `git add` and `git commit -a`
-(in v7 repositories), by `git annex import` and the assistant. It's
-also used by `git annex addurl` and `git annex importfeed` when downloading
-files. When a file does not match annex.largefiles, these commands will
-add its content to git instead of to the annex.
+You could take care to use `git annex add` after changes to the assets,
+but it would be easy to slip up and `git commit -a` (which runs `git add`),
+checking your large assets into git. Configuring annex.largefiles
+saves you the bother of keeping things straight when adding files.
+Once you've told git-annex what files are large, both `git annex add`
+and `git add`/`git commit -a` will add the large files to the annex and the
+small files to git.
 
-This saves you the bother of keeping things straight when adding files.
+Other commands that use the annex.largefiles configuration include
+`git annex import`, git annex addurl`, `git annex importfeed`, and
+the assistant.
 
 ## examples
 
@@ -34,11 +36,17 @@ Or, set the git configuration instead:
   
 	git config annex.largefiles 'largerthan=100kb and not (include=*.c or include=*.h)'
 
-Both of these settings do the same thing. Setting it in the `.gitattributes`
-file makes any checkout of the repository share that configuration, so is often
-a good choice. Setting the annex.largefiles git configuration lets different
-checkouts behave differently. The git configuration overrides the
-`.gitattributes` configuration.
+Both of these settings do the same thing. Setting it in the
+`.gitattributes` file makes any checkout of the repository share that
+configuration, so is often a good choice. Setting the annex.largefiles git
+configuration lets different checkouts behave differently. The git
+configuration overrides the `.gitattributes` configuration.
+
+Or, perhaps you just want all files to be added to the annex, no matter
+what. Just write "* annex.largefiles=anything" to the `.gitattributes`
+file, or run:
+
+	git config annex.largefiles anything
 
 ## syntax