Additions to southbound API interfaces

added API interfaces for topology

added rough API interfaces for flow

Change-Id: I84ee2b70dd33dcbca98c1863e7f1766cc02642c5
diff --git a/net/api/src/main/java/net/onrc/onos/api/flow/FlowDescription.java b/net/api/src/main/java/net/onrc/onos/api/flow/FlowDescription.java
new file mode 100644
index 0000000..80fc051
--- /dev/null
+++ b/net/api/src/main/java/net/onrc/onos/api/flow/FlowDescription.java
@@ -0,0 +1,12 @@
+package net.onrc.onos.api.flow;
+
+package net.onrc.onos.api.Description;
+
+/**
+ * Information about a flow rule.
+ */
+public interface FlowDescription extends Description {
+
+    // Match and action, possibly reason for flow rule, unless reason is too OF-specific.
+
+}