API definitions for the TE Topology Core App.

This APP creates and manages a hierarchy of TE topologies received from SBI TE provider and from user configurations from NBI.
The API contains internal data structures for TE attributes that are aligned with the TE attributes definition in standard IETF YANG TE topology model (https://tools.ietf.org/html/draft-ietf-teas-yang-te-topo-05).

This commit includes the following interface definitions:
- TE topology provider service, which is called by the TE topology provider from SB to pass TE topologies to the TE topology core APP
- TE topology service, which provides service APIs for an external APP to get/set TE topologies and their attributes.
- Network, Node, Link definitions for TE networks and their default class implementation

Change-Id: Iafcf6911b8d9e494397e3a255cae282bbca74d5c
diff --git a/apps/tetopology/BUCK b/apps/tetopology/BUCK
new file mode 100644
index 0000000..8a74315
--- /dev/null
+++ b/apps/tetopology/BUCK
@@ -0,0 +1,14 @@
+COMPILE_DEPS = [
+    '//lib:CORE_DEPS',
+]
+
+osgi_jar_with_tests (
+    deps = COMPILE_DEPS,
+)
+
+onos_app (
+    title = 'TE Topology Core App',
+    category = 'Traffic Steering',
+    url = 'http://onosproject.org',
+    description = 'Application to create and manage hierarchical TE topologies.',
+)