Ensuring up-to-date status for SDX-L2

Changes:
- Implements commands: sdxl2-clean
- Removes check for active circuit
- Removes intents when deleting SDX
- Adds completers: mac (sdxl2cp-add), placeholder, null
- Introduces enum-like for the VC types
- Modifies app name and description
- Updates README, pom, BUCK files
- Updates and refactors unit tests
- Reduces checkstyle warnings with more javadoc and restricted visibility

Change-Id: Ic672c81168e51690080d9d6466afe9f12b19e397
diff --git a/sdx-l2/BUCK b/sdx-l2/BUCK
index a24176b..9ea3f47 100644
--- a/sdx-l2/BUCK
+++ b/sdx-l2/BUCK
@@ -16,9 +16,9 @@
 )
 
 onos_app (
-  title = 'SDX-L2 Application',
+  title = 'SDX-L2 App',
   category = 'Utility',
   url = 'http://www.geant.org',
   included_bundles = BUNDLES,
-  description = 'SDX-L2 application for ONOS project developed by GEANT',
+  description = 'SDX-L2 application to create and manage Ethernet circuits',
 )
\ No newline at end of file