Small source movements (ccn_* to ccn/). Small change of NameBuilder implementation

diff --git a/model/ccn/README b/model/ccn/README
new file mode 100644
index 0000000..6b9ef69
--- /dev/null
+++ b/model/ccn/README
@@ -0,0 +1,2 @@
+This directory contains files borrowed and adapted from CCNx implementation
+