Add tool to rewrite licenses for the sample corpus

Change-Id: I1e4794b525bd3a112484f3b18abadbeb2bebdf6d
diff --git a/.gitignore b/.gitignore
index f2eb48a..f46ff07 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,7 +5,8 @@
 benchmark.csv
 docs
 todo.org
-tools
+tools/*
+!tools/rewrite_goe_licenses.pl
 build
 fixtures.txt
 node_modules