clarified build instructions + added pictorial instructions

Author: ghuntley

README.md

@@ -3,8 +3,11 @@ MvxTutorials
 
 To build this repo you need to include the MvvmCross binaries from https://github.com/slodge/MvvmCross-Binaries into /Lib/Mvx
 
-If you are on the PC include the VS2012 binaries - debug or release
+![](http://i.imgur.com/4mh5BR7.png)
+
+* Use MvvmCross-Binaries\VS2012\bin\[Debug|Release] if you are using Visual Studio and are not targeting Xamarin.iOS/Xamarin.Mac.
+* Use MvvmCross-Binaries\XS-iOS-Mac\bin\[Debug|Release] if you are using MonoDevelop (Xamarin Studio) or are developing for Xamarin.iOS/Xamarin.Mac.
+
+When setup, you should have an Mvx subfolder here with subfolders of 'Portable' plus one or more specific platforms
 
-If you are on the Mac include the iOS binaries - debug or release
 
-When setup, you should have an Mvx subfolder here with subfolders of 'Portable' plus one or more specific platforms