Add and start using Checkstyle 5.7

third_party/checkstyle/java.header

Index: third_party/checkstyle/java.header
diff --git a/third_party/checkstyle/java.header b/third_party/checkstyle/java.header
new file mode 100644
index 0000000000000000000000000000000000000000..0efd4ceccec6e8606d872fbbd3d18774492327d2
--- /dev/null
+++ b/third_party/checkstyle/java.header
@@ -0,0 +1,18 @@
+////////////////////////////////////////////////////////////////////////////////
+// checkstyle: Checks Java source code for adherence to a set of rules.
+// Copyright (C) 2001-2014  Oliver Burn
+//
+// This library is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public
+// License as published by the Free Software Foundation; either
+// version 2.1 of the License, or (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+////////////////////////////////////////////////////////////////////////////////