restore '-V' cmdline option for printing version

Preserves compatibility with pre-0.11 call, which was broken unnecessarily.

closes gh-926

IPython/config/application.py

@@ -393,7 +393,7 b' class Application(SingletonConfigurable):'
             self.print_examples()
             self.exit(0)
 
-        if '--version' in argv:
+        if '--version' in argv or '-V' in argv:
             self.print_version()
             self.exit(0)