Refactored how entry points work.

pre_commit_hooks/util.py

@@ -0,0 +1,16 @@
+
+import functools
+import sys
+
+
+def entry(func):
+    """Allows a function that has `argv` as an argument to be used as a
+    commandline entry.  This will make the function callable using either
+    explicitly passed argv or defaulting to sys.argv[1:]
+    """
+    @functools.wraps(func)
+    def wrapper(argv=None):
+        if argv is None:
+            argv = sys.argv[1:]
+        return func(argv)
+    return wrapper