Update README.md to let users know how to access stable/[milestone] versions of devstack. Other text cleanup as well.

Change-Id: Ic40106e40f65289cd276cb680509e0ff62745aa0

README.md

@@ -1,37 +1,42 @@
-Tool to quickly deploy openstack dev environments.
+Devstack is a set of scripts and utilities to quickly deploy an OpenStack cloud.
 
 # Goals
 
-* To quickly build dev openstack environments in clean oneiric environments
-* To describe working configurations of openstack (which code branches work together?  what do config files look like for those branches?)
-* To make it easier for developers to dive into openstack so that they can productively contribute without having to understand every part of the system at once
+* To quickly build dev OpenStack environments in a clean oneiric environment
+* To describe working configurations of OpenStack (which code branches work together?  what do config files look like for those branches?)
+* To make it easier for developers to dive into OpenStack so that they can productively contribute without having to understand every part of the system at once
 * To make it easy to prototype cross-project features
 
 Read more at http://devstack.org (built from the gh-pages branch)
 
-Be sure to carefully read these scripts before you run them as they install software and may alter your networking configuration.
+IMPORTANT: Be sure to carefully read stack.sh and any other scripts you execute before you run them, as they install software and may alter your networking configuration.  We strongly recommend that you run stack.sh in a clean and disposable vm when you are first getting started.
 
-# To start a dev cloud on your local machine (installing on a dedicated vm is safer!):
+# Versions
 
+The devstack master branch generally points to trunk versions of OpenStack components.  For older, stable versions, look for branches named stable/[mil
+estone].  For example, you can do the following to create a diablo OpenStack cloud:
+
+    git checkout stable/diablo
     ./stack.sh
 
-If working correctly, you should be able to access openstack endpoints, like:
+# To start a dev cloud (Installing in a dedicated, disposable vm is safer than installing on your dev machine!):
 
-* Horizon: http://myhost/
-* Keystone: http://myhost:5000/v2.0/
+    ./stack.sh
 
-# Customizing
+When the script finishes executing, you should be able to access OpenStack endpoints, like so:
 
-You can tweak environment variables by creating file name 'localrc' should you need to override defaults.  It is likely that you will need to do this to tweak your networking configuration should you need to access your cloud from a different host.
+* Horizon: http://myhost/
+* Keystone: http://myhost:5000/v2.0/
 
-# Todo
+We also provide an environment file that you can use to interact with your cloud via CLI:
 
-* Add python-novaclient cli support
-* syslog
-* Add volume support
-* Add quantum support
+    # source openrc file to load your environment with osapi and ec2 creds
+    . openrc
+    # list instances
+    nova list
+    # list instances using ec2 api
+    euca-describe-instances
 
-# Future
+# Customizing
 
-* idea: move from screen to tmux?
-* idea: create a live-cd / vmware preview image using this?
+You can override environment variables used in stack.sh by creating file name 'localrc'.  It is likely that you will need to do this to tweak your networking configuration should you need to access your cloud from a different host.