Refactor logic from gerrit.sh into gerrit/filters.  Add modular usage/help

Change-Id: I2ff1d0eda2bb7e80dab8d345721f39c621357774
diff --git a/gerrit/makefile b/gerrit/makefile
new file mode 100644
index 0000000..73f6aec
--- /dev/null
+++ b/gerrit/makefile
@@ -0,0 +1,11 @@
+# -*- makefile -*-
+
+all:
+
+test ::
+
+clean ::
+
+sterile :: clean
+
+# [EOF]