title: Android Support Package / Compatibility Library - use v4 or v13?
body: <p>I've just read this description of the Android Support Package / Compatibility Library...</p>
  
  <p><a href="http://developer.android.com/sdk/compatibility-library.html" rel="noreferrer">http://developer.android.com/sdk/compatibility-library.html</a></p>
  
  <p>... and it's left me a little confused! It says that the v13 library is a superset of v4 but I thought it was the other way around?</p>
  
  <p>Getting practical: If I want to use the compatibility library such that my app builds and works fine for phones running Android 2.2 (API 8) through to 4.0 (API 14) and beyond, will v4 suffice for me?</p>