Add a basic tutorial for the tools in depot_tools.

docs/man1/git-upstream-diff.1

Index: docs/man1/git-upstream-diff.1
diff --git a/docs/man1/git-upstream-diff.1 b/docs/man1/git-upstream-diff.1
index ae479173fd22d517cb945e8b0be8c07d6071f0a4..fbe57af2555667b1658dfce7ec0babe2e679167e 100644
--- a/docs/man1/git-upstream-diff.1
+++ b/docs/man1/git-upstream-diff.1
@@ -2,12 +2,12 @@
 .\"     Title: git-upstream-diff
 .\"    Author: [FIXME: author] [see http://docbook.sf.net/el/author]
 .\" Generator: DocBook XSL Stylesheets v1.78.1 <http://docbook.sf.net/>
-.\"      Date: 03/25/2014
+.\"      Date: 04/10/2014
 .\"    Manual: Chromium depot_tools Manual
-.\"    Source: depot_tools 207bff1
+.\"    Source: depot_tools 68b1017
 .\"  Language: English
 .\"
-.TH "GIT\-UPSTREAM\-DIFF" "1" "03/25/2014" "depot_tools 207bff1" "Chromium depot_tools Manual"
+.TH "GIT\-UPSTREAM\-DIFF" "1" "04/10/2014" "depot_tools 68b1017" "Chromium depot_tools Manual"
 .\" -----------------------------------------------------------------
 .\" * Define some portability stuff
 .\" -----------------------------------------------------------------
@@ -110,7 +110,7 @@ Some common short\-hand aliases\&. Feel free to add these to your \fI~/\&.gitcon
 \fBgit-rebase-update\fR(1)
 .SH "CHROMIUM DEPOT_TOOLS"
 .sp
-Part of the chromium \fBdepot_tools\fR(1) suite\&. These tools are meant to assist with the development of chromium and related projects\&. Download the tools from \m[blue]\fBhere\fR\m[]\&\s-2\u[1]\d\s+2\&.
+Part of the chromium \fBdepot_tools\fR(7) suite\&. These tools are meant to assist with the development of chromium and related projects\&. Download the tools from \m[blue]\fBhere\fR\m[]\&\s-2\u[1]\d\s+2\&.
 .SH "NOTES"
 .IP " 1." 4
 here