Update Python + Virtualenv.sublime-build

allow builds to be cancelled
AdrianLC#14

Author: Cernunnos

Python + Virtualenv.sublime-build

@@ -2,5 +2,6 @@
     "target": "virtualenv_exec",
     "shell_cmd": "python -u \"$file\"",
     "file_regex": "^[ ]*File \"(...*?)\", line ([0-9]*)",
-    "selector": "source.python"
+    "selector": "source.python",
+    "cancel": {"kill": true}
 }