Add cli argument to use different .topo or .params files

- Add cli arguments
- Refactor xmlparser functions
- Cleaned up and fixed some logging
- main.testDir is now set to the directory where the test file is
  located
- main.testsRoot is now set to the full path of TestON/tests/
    - Fixed usages accordingly

Change-Id: I2a0f0c3728b5732b242a2e860e6538a6f3b65166
diff --git a/TestON/tests/PLAT/PLATdockertest/PLATdockertest.py b/TestON/tests/PLAT/PLATdockertest/PLATdockertest.py
index d871fae..bc4f3c3 100644
--- a/TestON/tests/PLAT/PLATdockertest/PLATdockertest.py
+++ b/TestON/tests/PLAT/PLATdockertest/PLATdockertest.py
@@ -91,7 +91,7 @@
         NODElist = main.params[ "SCALE" ][ "nodelist" ].split( ',' )
         main.log.info( "onos container names are: " + ",".join( NODElist ) )
         IPlist = list()
-        main.testOnDirectory = re.sub( "(/tests)$", "", main.testDir )
+        main.testOnDirectory = re.sub( "(/tests)$", "", main.testsRoot )
         CTIDlist = list()
 
         main.log.info( "Check docker status, it not running, try restart it" )