Update the Readme with better instructions

README.markdown

@@ -1,3 +1,23 @@
 # AutomationExample
 
-This is a demo app to showcase how to run UI Automation scripts from the command line.
+This is a demo app to showcase how to run UI Automation scripts from the
+command line.
+
+# Requirements
+
+You need to have at least Xcode 4.3, but know that UI Automation broke under
+Xcode 4.4 as it was released with 10.8 Mountain Lion. As of Xcode 4.5 DP4, UI
+Automation works great again, so you'll want to jump to that version if you
+don't want to use Xcode 4.3.
+
+# Running The Demo
+
+Just open a terminal window, change to the project directory and run this:
+
+    ./run_automation.sh
+
+It will build the application with `xcodebuild` in the `/tmp` directory and
+then execute it with my `unix_instruments` wrapper that ensures that
+Instruments returns a proper exist status code when a test fails. You can read
+more about how that works in the copious comments.
+