README.md: update and simplify

Fixes #18675

Change-Id: I82e63e8ee3fe4a998b01d9397c3045912588e2f5
Reviewed-on: https://go-review.googlesource.com/35183
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

README.md

@@ -5,39 +5,37 @@ reliable, and efficient software.
 
 ![Gopher image](doc/gopher/fiveyears.jpg)
 
-For documentation about how to install and use Go,
-visit https://golang.org/ or load doc/install-source.html
-in your web browser.
-
 Our canonical Git repository is located at https://go.googlesource.com/go.
 There is a mirror of the repository at https://github.com/golang/go.
 
+Unless otherwise noted, the Go source files are distributed under the
+BSD-style license found in the LICENSE file.
+
+### Download and Install
+
+#### Binary Distributions
+
+Official binary distributions are available at https://golang.org/dl/.
+
+After downloading a binary release, visit https://golang.org/doc/install
+or load doc/install.html in your web browser for installation
+instructions.
+
+#### Install From Source
+
+If a binary distribution is not available for your combination of
+operating system and architecture, visit
+https://golang.org/doc/install/source or load doc/install-source.html
+in your web browser for source installation instructions.
+
+### Contributing
+
 Go is the work of hundreds of contributors. We appreciate your help!
 
 To contribute, please read the contribution guidelines:
 	https://golang.org/doc/contribute.html
 
-##### Note that we do not accept pull requests and that we use the issue tracker for bug reports and proposals only. Please ask questions on https://forum.golangbridge.org or https://groups.google.com/forum/#!forum/golang-nuts.
+Note that the Go project does not use GitHub pull requests, and that
-
+we use the issue tracker for bug reports and proposals only. See
-Unless otherwise noted, the Go source files are distributed
+https://golang.org/wiki/Questions for a list of places to ask
-under the BSD-style license found in the LICENSE file.
+questions about the Go language.
-
---
-
-## Binary Distribution Notes
-
-If you have just untarred a binary Go distribution, you need to set
-the environment variable $GOROOT to the full path of the go
-directory (the one containing this file).  You can omit the
-variable if you unpack it into /usr/local/go, or if you rebuild
-from sources by running all.bash (see doc/install-source.html).
-You should also add the Go binary directory $GOROOT/bin
-to your shell's path.
-
-For example, if you extracted the tar file into $HOME/go, you might
-put the following in your .profile:
-
-	export GOROOT=$HOME/go
-	export PATH=$PATH:$GOROOT/bin
-
-See https://golang.org/doc/install or doc/install.html for more details.