Ignore all Python 3 virtual environments

How soon could Python 4 happen anyway? :-P
diff --git a/.gitignore b/.gitignore
index 5e38f5f..5ccad2e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -16,7 +16,7 @@
 dist/
 *.egg
 py27/
-py34/
+py3[0-9]*/
 
 # Node installation output
 node_modules