Added updateproxy command and remote.name.annex-proxy configuration

So far this only records proxy information on the git-annex branch.

doc/git-annex-updateproxy.mdwn

@@ -0,0 +1,39 @@
+# NAME
+
+git-annex updateproxy - update records with proxy configuration
+
+# SYNOPSIS
+
+git annex updateproxy
+
+# DESCRIPTION
+
+A git-annex repository can act as a proxy for its remotes. That allows
+annexed content to be stored and removed from the proxy's remotes, by
+repositories that do not have a direct connection to the remotes.
+
+By default, no proxying is done. To configure the local repository to act
+as a proxy for its remote named "foo", run `git config remote.foo.annex-proxy`
+true`.
+
+After setting or unsetting `remote.<name>.annex-proxy` git configurations,
+run `git-annex updateproxy` to record the proxy configuration in the
+git-annex branch. That tells other repositories about the proxy
+configuration.
+
+Suppose, for example, that remote "work" has had this command run in
+it. Then git-annex will know about an additional remote, "work-foo".
+
+# OPTIONS
+
+* The [[git-annex-common-options]](1) can be used.
+
+# SEE ALSO
+
+[[git-annex]](1)
+
+# AUTHOR
+
+Joey Hess <id@joeyh.name>
+
+Warning: Automatically converted into a man page by mdwn2man. Edit with care.

doc/git-annex.mdwn

@@ -252,7 +252,6 @@ content from the key-value store.
   
   See [[git-annex-configremote]](1) for details.
 
-
 * `renameremote`
 
   Renames a special remote.
@@ -327,6 +326,12 @@ content from the key-value store.
   
   See [[git-annex-required]](1) for details.
 
+* `updateproxy`
+
+  Update records with proxy configuration.
+  
+  See [[git-annex-updateproxy](1) for details.
+
 * `schedule repository [expression]`
 
   Get or set scheduled jobs.
@@ -1640,6 +1645,12 @@ Remotes are configured using these settings in `.git/config`.
   content of any file, even though its normal location tracking does not
   indicate that it does. This will cause git-annex to try to get all file
   contents from the remote. Can be useful in setting up a caching remote.
+	
+* `remote.<name>.annex-proxy`
+
+  Set to "true" to make the local repository able to act as a proxy to this
+  remote. After configuring this, run [[git-annex-updateproxy](1) to store
+  the new configuration in the git-annex branch.
 
 * `remote.<name>.annex-private`
 

doc/internals.mdwn

@@ -308,6 +308,21 @@ For example, this logs that a remote has an object stored using both
 
 (When those chunks are removed from the remote, the 9 is changed to 0.)
 
+## `proxy.log`
+
+Used to record what repositories are accessible via a proxy.
+
+Each line starts with a timestamp, then the uuid of the repository
+that can serve as a proxy, and then a list of the remotes that it can
+proxy to, separated by spaces.
+
+Each remote in the list consists of a uuid, followed by a colon (`:`)
+and then a remote name.
+	
+For example:
+
+    1317929100.012345s e605dca6-446a-11e0-8b2a-002170d25c55 26339d22-446b-11e0-9101-002170d25c55:foo c076460c-2290-11ef-be53-b7f0d194c863:bar
+
 ## `schedule.log`
 
 Used to record scheduled events, such as periodic fscks.