Add a jenkins email presend script. To begin with just removes threading headers.
diff --git a/jenkins-dsl/cassandra_email_presend.groovy b/jenkins-dsl/cassandra_email_presend.groovy
new file mode 100644
index 0000000..ab6a51d
--- /dev/null
+++ b/jenkins-dsl/cassandra_email_presend.groovy
@@ -0,0 +1,2 @@
+msg.removeHeader("In-Reply-To")
+msg.removeHeader("References")