[RELEASE] Released version 1.7-dev0

Released version 1.7-dev0 with the following main changes :
    - exact copy of 1.6.0
diff --git a/VERSION b/VERSION
index dc1e644..8d25575 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-1.6.0
+1.7-dev0