migrate to dhtnet namespace

Change-Id: I7143a010bd83e8cfa7a3c8c3072ed23f6f0ba8e3
diff --git a/include/generic_io.h b/include/generic_io.h
index cd8d0e9..db0ce33 100644
--- a/include/generic_io.h
+++ b/include/generic_io.h
@@ -29,7 +29,7 @@
 using ssize_t = SSIZE_T;
 #endif
 
-namespace jami {
+namespace dhtnet {
 
 template<typename T>
 class GenericSocket